Yunhye Kim

Altered frequency and migration capacity of CD4+CD25+ regulatory T cells in systemic lupus erythematosus

OBJECTIVES To determine the frequency and chemokine receptor-related migratory capacity of CD4(+)CD25(+) regulatory T cells (Tregs) and their association with clinical parameters in patients with SLE. METHODS The expression of CD4, CD25, FoxP3 and CCR4 was examined with flow cytometry after staining with fluorescence-conjugated antibodies in 20 patients with SLE, 20 patients with RA and 21 age- and sex-matched healthy controls. For analysis of migration capacity in 24-well chemotaxis chambers, sorted cells were stimulated with ligands of CCR4, CCL17 and CCL22 and analysed with FACScan. Correlations between the number of Tregs and CCR4(+) Treg cells and clinical parameters were analysed. RESULTS The numbers of Tregs(bright) and CCR4(+) Tregs(bright) were significantly decreased in the patients with SLE compared with healthy controls. The number of Tregs(bright) was negatively correlated with the levels of anti-dsDNA antibody and the number of CCR4(+) Tregs(bright) had a positive correlation with the levels of C(3). Percentage of migrated Tregs(bright) by CCL17 or CCL22 was significantly decreased in the patients with SLE compared with healthy controls. CONCLUSIONS These results suggest that altered frequency of Tregs and CCR4(+) Tregs(bright) and decreased migratory capacity of Tregs might be involved in the pathogenesis of SLE and indicate that targeting the Tregs can be a new therapeutic strategy in SLE.

Production of dyestuffs from indole derivatives by naphthalene dioxygenase and toluene dioxygenase.

Aims: To isolate and characterize the phorate [O,O‐diethyl‐S‐(ethylthio)methyl phosphoradiothioate] degrading bacteria from agricultural soil, and their assessment for multifarious biological activities of environmental and agronomic significance.

Short communication: Development of a direct in vivo screening model to identify potential probiotic bacteria using Caenorhabditis elegans

Caenorhabditis elegans is an accepted model host to study host-bacteria interactions in the gut, in addition to being a simple model with which to study conserved aspects of biological signaling pathways in intestinal environments, because these nematode worms have similar intestinal cells to those of humans. Here, we used C. elegans to develop a new in vivo screening system for potential probiotic lactic acid bacteria (LAB). Initially, critical colonization ability of LAB strains isolated from Korean infant feces was screened in the worm intestinal tract over a period of 5 d. Furthermore, we investigated host health-promoting activities, including longevity-extending effects and immune-enhancing activities against foodborne pathogen infection. We identified 4 LAB strains that were highly persistent in the nematode gut and that significantly prolonged the longevity of C. elegans and improved the survival of C. elegans in response to infection by Staphylococcus aureus. The 4 LAB strains we identified showed resistance to acid and bile conditions, assimilated cholesterol, and were able to attach to a mucus layer. The 4 LAB isolates were identified as Lactobacillus plantarum using 16S rRNA sequencing analysis. Taken together, we developed a direct in vivo screening system using C. elegans to study host health-promoting LAB. Our system is simple, rapid, cost-effective, and reliable, and we anticipate that this system will result in the discovery of many more potential probiotic bacteria for dairy foods.

Short communication: In vivo screening platform for bacteriocins using Caenorhabditis elegans to control mastitis-causing pathogens

This study aimed to develop an in vivo screening platform using Caenorhabditis elegans to identify a novel bacteriocin for controlling the mastitis-causing pathogen Staphylococcus aureus strain RF122 in dairy cows. Using Bacillus spp. isolated from traditional Korean foods, we developed a direct in vivo screening platform that uses 96-well plates and fluorescence image analysis. We identified a novel bacteriocin produced by Bacillus licheniformis strain 146 (lichenicin 146) with a high in vivo antimicrobial activity using our liquid C. elegans-Staph. aureus assay. We also determined the characteristics of lichenicin 146 using liquid chromatography-mass spectrometry and confirmed that it shared homologous sequences with bacteriocin family proteins. In addition, RNA-sequencing analysis revealed genes encoding cell surface or membrane proteins (SAB0993c, SAB0150, SAB0994c, and SAB2375c) that are involved in the bactericidal activity of lichenicin 146 against Staph. aureus strain RF122 infection as well as those encoding transcriptional regulators (SAB0844c and SAB0133). Thus, our direct in vivo screening platform facilitates simple, convenient, cost-effective, and reliable screening of potential antimicrobial compounds with applications in the dairy field.

Optimization of low-temperature blanching combined with calcium treatment to inactivate Escherichia coli O157: H7 on fresh-cut spinach

To develop a mild blanching method with calcium salts to ensure microbiological safety and quality of fresh‐cut spinach.

Mulberry leaf extract fermented with Lactobacillus acidophilus A4 ameliorates 5-fluorouracil-induced intestinal mucositis in rats

The objective of the present study was to evaluate the effect of mulberry leaf extract (ME) fermented with Lactobacillus acidophilus A4 (A4) on intestinal mucositis induced by 5‐fluorouracil (5‐FU) in a rat model. Male Wistar rats were gavaged with A4, ME, fermented mulberry leaf extract FME) or lafutidine (LAF) for 10 days and injected intraperitoneally with 5‐FU (150 mg kg−1) or saline (normal control) on day 7 to induce mucositis. After euthanizing the animals, their small and large intestines were removed for evaluation of histopathologic parameters, myeloperoxidase (MPO) activity, mucin content, and mRNA expression of the mucin gene and pro‐inflammatory cytokine interleukin (IL)‐1β. 5‐FU induced significant weight loss, shortened villi height, and increased histological severity, IL‐1β expression, and MPO activity compared to the normal control group. These pathological changes were markedly ameliorated by treatment with A4, ME and FME. These treatments also stimulated MUC2 and MUC5AC gene expression and mucin production, and reduced IL‐1β expression and MPO level. Interestingly, FME had the greatest protective effect on 5‐FU‐induced mucositis in rats.

Heat-killed Lactobacillus spp. cells enhance survivals of Caenorhabditis elegans against Salmonella and Yersinia infections.

This study examined the effect of feeding heat‐killed Lactobacillus cells on the survival of Caenorhabditis elegans nematodes after Salmonella Typhimurium and Yersinia enterocolitica infection. The feeding of heat‐killed Lactobacillus plantarum 133 (LP133) and Lactobacillus fermentum 21 (LP21) cells to nematodes was shown to significantly increase the survival rate as well as stimulate the expression of pmk‐1 gene that key factor for C. elegans immunity upon infection compared with control nematodes that were only fed Escherichia coli OP50 (OP50) cells. These results suggest that heat‐killed LP133 and LF21 cells exert preventive or protective effects against the Gram‐negative bacteria Salm. Typhimurium and Y. enterocolitica. To better understand the mechanisms underlying the LF21‐mediated and LP133‐mediated protection against bacterial infection in nematodes, transcriptional profiling was performed for each experimental group. These experiments showed that genes related to energy generation and ageing, regulators of insulin/IGF‐1‐like signalling, DAF genes, oxidation and reduction processes, the defence response and/or the innate immune response, and neurological processes were upregulated in nematodes that had been fed heat‐killed Lactobacillus cells compared with nematodes that had been fed E. coli cells.

Rate of left ventricular pressure change by Doppler echocardiography in dogs with chronic mitral valve disease at different stages of congestive heart failure

Although the major pathological feature of chronic mitral valve disease is mitral regurgitation, myocardial dysfunction has been suggested to be present in dogs with chronic mitral valve disease. However, accurate assessment of myocardial function remains challenging. Doppler-derived rate of left ventricular pressure change is a simple, less load-dependent method for evaluating myocardial function. We aimed to evaluate Doppler-derived rate of left ventricular pressure change for assessing myocardial function in different stages of dogs with chronic mitral valve disease. This analytical cross-sectional study recruited 55 client-owned dogs with chronic mitral valve disease prospectively. Based on physical examination, indirectly measured blood pressure, routine hematologic and biochemistry examinations, thoracic radiography, electrocardiography, and echocardiography, dogs were diagnosed as mitral valve disease and excluded for systemic diseases and other cardiac diseases. They were classified according to the International Small Animal Cardiac Health Council scales. Doppler-derived rates of left ventricular pressure rise and fall (dP/dt and -dP/dt) were analyzed by two investigators using continuous-wave Doppler imaging. Doppler-derived dP/dt was higher in dogs of class IIIa than in those of the other classes, whereas values of -dP/dt decreased significantly with the severity of congestive heart failure. The peak velocity of the early diastolic wave and -dP/dt were identified as independent predictors of congestive heart failure. Our findings suggested that Doppler-derived dP/dt and -dP/dt, used in combination with conventional echocardiographic variables, could allow a better understanding of myocardial dysfunction and a possibility for prediction of the risk of heart failure in dogs with chronic mitral valve disease.