Prevalence of Gymnophalloides seoi infection in coastal villages of Haenam-gun and Yeongam-gun, Republic of Korea

One coastal village in Haenam-gun and two in Yeongam-gun, Jeollanam-do were surveyed for intestinal parasite infections by fecal examination. The egg positive rates of Gymnophalloides seoi were high, 24.1% (14/58) in Haenam-gun and 9.3% (11/118) in Yeongam-gun. The egg positive rates of heterophyids, including Heterophyes nocens, and of Clonorchis sinensis were 10.3% and 6.9% in Haenam-gun, and 14.4% and 8.5% in Yeongam-gun, respectively. After praziquantel treatment and purgation, a total of 37,761 fluke specimens were recovered from 17 patients; 11 in Haenam-gun and 6 in Yeongam-gun. Gymnophalloides seoi was the most commonly recovered species, with 37,489 specimens in total (2,205 per person). Other recovered flukes included Heterophyes nocens, Stictodora fuscata, Heterophyopsis continua, Pygidiopsis summa, and undetermined species. These results indicate that the areas surveyed are new endemic foci of G. seoi.     

Purification and characterization of a cytosolic, 42-kDa and Ca2+-dependent phospholipase A2 from bovine red blood cells: its involvement in Ca2+-dependent release of arachidonic acid from mammalian red blood cells

It has become evident that a Ca(2+)-dependent release of arachidonic acid (AA) and subsequent formation of bioactive lipid mediators such as prostaglandins and leukotrienes in red blood cells (RBCs) can modify physiological functions of neighboring RBCs and platelets. Here we identified a novel type of cytosolic PLA(2) in bovine and human RBCs and purified it to apparent homogeneity with a 14,000-fold purification. The purified enzyme, termed rPLA(2), has a molecular mass of 42 kDa and reveals biochemical properties similar to group IV cPLA(2), but shows different profiles from cPLA(2) in several column chromatographies. Moreover, rPLA(2) did not react with any of anti-cPLA(2) and anti-sPLA(2) antibodies and was identified as an unknown protein in matrix-assisted laser desorption/ionization time-of-flight mass spectrometric analysis. Divalent metal ions tested exhibited similar effects between rPLA(2) and cPLA(2), whereas mercurials inhibited cPLA(2) but had no effect on rPLA(2). Antibody against the 42-kDa protein not only precipitated the rPLA(2) activity, but also reacted with the 42-kDa protein from bovine and human RBCs in immunoblot analysis. The 42-kDa protein band was selectively detected in murine fetal liver cells known as a type of progenitor cells of RBCs. It was found that EA4, a derivative of quinone newly developed as an inhibitor for rPLA(2), inhibited a Ca(2+) ionophore-induced AA release from human and bovine RBCs, indicating that this enzyme is responsible for the Ca(2+)-dependent AA release from mammalian RBCs. Finally, erythroid progenitor cell assay utilizing diaminobenzidine staining of hemoglobinized fetal liver cells showed that rPLA(2) detectable in erythroid cells was down-regulated when differentiated to non-erythroid cells. Together, our results suggest that the 42-kDa rPLA(2) identified as a novel form of Ca(2+)-dependent PLA(2) may play an important role in hemostasis, thrombosis, and/or erythropoiesis through the Ca(2+)-dependent release of AA.     

Bacterial persisters tolerate antibiotics by not producing hydroxyl radicals

In a phenomenon called persistence, small numbers of bacterial cells survive even after exposure to antibiotics. Recently, bactericidal antibiotics have been demonstrated to kill bacteria by increasing the levels of hydroxyl radicals inside cells. In the present study, we report a direct correlation between intracellular hydroxyl radical formation and bacterial persistence. By conducting flow cytometric analysis in a three-dimensional space, we resolved distinct bacterial populations in terms of intracellular hydroxyl radical levels, morphology and viability. We determined that, upon antibiotic treatment, a small sub-population of Escherichia coli survivors do not overproduce hydroxyl radicals and maintain normal morphology, whereas most bacterial cells were killed by accumulating hydroxyl radicals and displayed filamentous morphology. Our results suggest that bacterial persisters can be formed once they have transient defects in mediating reactions involved in the hydroxyl radical formation pathway. Thus, it is highly probable that persisters do not share a common mechanism but each persister cell respond to antibiotics in different ways, while they all commonly show lowered hydroxyl radical formation and enhanced tolerance to antibiotics.     

Betulinic and oleanolic acids isolated from Forsythia suspensa Vahl inhibit urease activity of Helicobacter pylori

Sixteen medicinal herbs were selected from a database on traditional herbal materials as well as literature on Korean plant resources. Then ethanol (70%, v/v) extracts of these herbs were tested for inhibition of the urease activity of Helicobacter pylori. The urease activity of H. pylori was strongly (82%) inhibited by extract of Forsythia suspensa Vahl. Active compounds in extract of Forsythia suspensa Vahl were first separated by batch mode solvent extraction, followed by purification by silica gel and octadecyl silica gel column chromatography using solvents of different polarity. According to NMR analysis of the last chromatographic fraction, we identified the presence of betulinic acid and oleanolic acid, which are known to have anti-inflammatory, anti-cancer, and anti-HIV viral activities.     

Distribution of anticancer antibiotic daunomycin in the rat heart and kidney revealed by immunocytochemistry using monoclonal antibodies

Two monoclonal antibodies (ADM-1-11 and 79-31 mAbs) were raised against daunomycin (DM) conjugated to bovine serum albumin via the cross-linker N-(gamma-maleimidobutyryloxy)succinimide. The monoclonal antibodies (mAbs) specifically detected DM as well as its analogs doxorubicin and epirubicin, but did not react with other anticancer antibiotics, including pepleomycin, mitomycin C, and actinomycin D. The mAbs reacted strongly with glutaraldehyde-conjugated DM in an enzyme linked immunosorbent assay (ELISA) used as a model system for immunocytochemistry as well as in appropriately pretreated sections of tissues from animals injected with DM. No staining occurred in tissues from uninjected animals. In order to perform DM ICC a number of tissue treatment conditions critical to the detection of low molecular weight substances were employed. Uptake of DM was studied in rats after a single i.v. or i.p. administration of the drug. In the heart, accumulation of DM occurred in nuclei and in the cytoplasm. In the kidney, DM immunoreactivity accumulated in all segments of the nephron except for the proximal tubules. Since the proximal tubules are known to be where a variety of transport systems including P-glycoprotein (Pgp) and organic anion-transporting polypeptides (OATPs) in drug interactions occur, the absence of DM accumulation in these segments may reflect a transport phenomenon depending upon such transporters. The availability of methods to study sites of accumulation of DM offers possibilities for understanding toxic side effects of this drug on the heart and kidney. Moreover, the immunocytochemical methodology developed may prove useful for the localization of other low molecular weight drugs that can be fixed in situ by glutaraldehyde.     

Lipase-catalyzed synthesis of sorbitol-fatty acid esters at extremely high substrate concentrations

Lipase-catalyzed synthesis of sorbitol-fatty acid esters was performed in eutectic media with extremely high substrate concentrations. Homogeneous eutectic melts of sorbitol and fatty acids of C6-C16 were prepared using an adjuvant mixture. Enhanced homogeneity of mixtures was confirmed by X-ray diffraction analysis. The substrate concentration was 3.63-6.67 M in the eutectic media, whereas in organic media the concentration was below 0.10 M. Esters were synthesized with an immobilized Candida antarctica lipase, and optimum conditions were analyzed. Compared to reactions in organic media, the initial reaction rate of ester synthesis and the overall productivity were significantly enhanced in eutectic media while the conversion yields were similar. Based on the kinetic analysis, highly viscous eutectic media were shown to influence the initial reaction rate and the apparent activation energy resulting in diffusion limitations.     

Fluid shear regulates the kinetics and receptor specificity of Staphylococcus aureus binding to activated platelets

The interaction between surface components on the invading pathogen and host cells such as platelets plays a key role in the regulation of endovascular infections. However, the mechanisms mediating Staphylococcus aureus binding to platelets under shear remain largely unknown. This study was designed to investigate the kinetics and molecular requirements of platelet-S. aureus interactions in bulk suspensions subjected to a uniform shear field. Hydrodynamic shear-induced collisions augment platelet-S. aureus binding, which is further potentiated by platelet activation with stromal derived factor-1beta. Peak adhesion efficiency occurs at low shear (100 s(-1)) and decreases with increasing shear. The molecular interaction of platelet alpha(IIb)beta(3) with bacterial clumping factor A through fibrinogen bridging is necessary for stable bacterial binding to activated platelets under shear. Although this pathway is sufficient at low shear (相似文献   

Insecticide susceptibility of Ephemera orientalis (Ephemeroptera: Ephemeridae) and two mosquito species,Anopheles sinensis and Culex pipiens in the Republic of Korea

Field-collected populations of mayflies, Ephemera orientalis were tested for susceptibility to 10 different insecticides using a direct-contact mortality bioassay. Ephemera orientalis subimagoes were susceptible to the insecticides chlorpyrifos, fenitrothion and chlorfenapyr with LD₅₀ values of 69.7, 78.8 and 81.9 μg/♀, and adults had LD₅₀ values of 71.9, 78.8 and 85.4 μg/♀, respectively. Susceptibility ratios (SRs) of subimagoes and adults of E. orientalis to the 10 insecticides were 1.0 to1.2 folds. The mayflies showed higher susceptibility to organophosphates than to pyrethroids. The SRs of Anopheles sinensis to E. orientalis were 514 to 1438 folds higher for organophosphates (LD₅₀ values of 0.05 to 0.23 μg/♀) and 62 to 1155 folds higher for pyrethroids (LD₅₀ values of 0.13 to 2.41 μg/♀). The SRs of Culex pipiens to E. orientalis were 606 to 3595 folds higher for organophosphates with LD₅₀ values of 0.02–0.17 μg/♀ and 81 to 1365 folds higher for pyrethroids with LD₅₀ values of 0.11–1.83 μg/♀. These results indicate that the use of ineffective insecticides will result in unsatisfactory control against field populations of the subimagoes and adults of E. orientalis.     

Effects of UCP2 and UCP3 Variants on the Manifestation of Overweight in Korean Children

To investigate the associations of uncoupling protein (UCP)2 and UCP3 gene variants with overweight and related traits, we genotyped UCP2−866G>A, UCP2Ala55Val, and UCP3−55C>T in 737 Korean children and 732 adults and collected data regarding anthropometric status and blood biochemistry. Information concerning the children's lifestyles and dietary habits was collected. The UCP2−866G>A and UCP3−55C>T gene variants showed significant associations with BMI level, waist circumference, and body weight in the children but not in the adults. Compared with −866GG carriers, the −866GA and AA carriers showed a strong decreasing trend in the risk for overweight (odds ratio (OR), 0.67; 95% confidence interval (CI), 0.45–1.01; P = 0.053). In comparison with UCP3−55CC carriers, children carrying −55CT and TT showed a significant reduction in the risk of overweight (OR, 0.67; 95% CI, 0.46–0.98; P = 0.039). There was also evidence of interactions between the effects of the combined UCP2−UCP3 genotype and obesity‐related metabolic traits. The greatest protective effect against overweight was seen in those with the combined genotype non‐UCP2−866GG and non‐UCP3−55CC, as compared with those carrying both UCP2−866GG and UCP3−55CC (OR, 0.60; 95% CI, 0.38–0.95; P = 0.030). In the subgroup with a low level of physical activity, UCP3−55CC carriers had higher BMI values than UCP3−55T carriers (16.6 ± 2.3 kg/m² vs. 16.1 ± 1.9 kg/m², P = 0.016). Low physical activity may aggravate the susceptibility to overweight in UCP2−866GG and UCP3−55CC carriers.