• Fisheries and Aquatic Sciences
• /
• v.1 no.2
• /
• pp.187-191
• /
• 1998

Chemotherapy can not be applied for the control of fish viral diseases because viruses depend on host machinery for their replication. Although new control strategies including vaccination are under development, avoidance of virus introduction by rapid and correct diagnosis is the best way of fish viral disease control. Although observation of virus particles with an electron microscope is an easy method for virus detection, it take a few days for the sample preparation. In order to shorten the sample preparation time, microwave radiation was applied in the procedure. With this method, 15 seconds was enough for fixation of virus infected fish samples or cultured cells inoculated with infectious hematopoietic necrosis virus, which takes 2-4 hours with routine methods. Also four minutes was enough for polymerization of embedding resin which takes 24-48 hours with routine methods. Samples prepared with microwave were good enough for direct electron microscopic observation and immunogold labeling assay.

• The Korean Journal of Food And Nutrition
• /
• v.29 no.3
• /
• pp.341-346
• /
• 2016

Phagocytosis is a primary and an essential step of host defense, and is triggered by the interaction of particles with specific receptor of macrophages. In this study, we investigated the effect of extracts of Rudbeckia laciniata (RLE) on the phagocytic activity of macrophage, by monitoring the phagocytosis-associated signal transduction. RLE markedly increased phagocytosis of serum-opsonized zymosan particles (SOZ), while phagocytosis of IgG-opsonized zymosan particles (IOZ) or none-opsonized zymosan particles (NOZ) remained unaffected. However, RLE did not affect the binding of opsonized zymosan particles (OZ) with the cell surface of macrophage. This suggests that RLE may regulate SOZ-induced intracellular signaling during phagocytosis of macrophage. To confirm this hypothesis, we investigated whether RLE was involved in the RhoA-mediated signal transduction during phagocytosis of SOZ. Inhibitors of the RhoA-mediated signaling pathway, such as Y-27632 (for ROCK), ML-7 (for MLCK), and Tat-C3 (for RhoA), totally blocked phagocytosis of SOZ enhanced by RLE, as well as phagocytosis of SOZ. Additionally, RhoA activity was markedly increased when cells were treated with RLE, suggesting that RLE could increase the phagocytic activity of macrophage via RhoA-ROCK/MLCK signal pathway. Thus, RLE may be used to develop functional foods for immunity.

• Food Science of Animal Resources
• /
• v.33 no.2
• /
• pp.229-238
• /
• 2013

Lactic acid bacteria (LAB) are added to different food products for a long time due to health beneficial effects on human host. LAB is applied in dairy products, such as yoghurt, cheese, and various fermented products, and also in non-dairy products, such as sausages. However, reaching the human gut alive as well as in a sufficient cell amount to exert positive health effects is still a big challenge, due to LAB sensitive character and vulnerability against harsh and detrimental conditions in human digestive system. Keeping physiological activity of sensitive LAB strains alive is for the formulation of novel food products with a probiotic health claim of utmost interest, thus microencapsulation has been applied and investigated as a promising technique for a good and reliable protection. Microencapsulation allows reduced cell injury or cell loss by retaining cells within the encapsulating membrane and can be enforced by spray-drying, emulsion, extrusion, and a range of other technologies in combination with an appropriate coating material, such as alginate, chitosan, and mixture of these two polymers. In this review, established and well-studied microencapsulation techniques with their favored coating materials, as well as the recent applications of microencapsulated LAB into dairy products will be discussed.

• Journal of Microbiology and Biotechnology
• /
• v.26 no.2
• /
• pp.432-439
• /
• 2016

Shiga toxins (Stxs) produced by Shiga toxin-producing Escherichia coli (STEC) strains are major virulence factors that cause fatal systemic complications, such as hemolytic uremic syndrome and disruption of the central nervous system. Although numerous studies report proinflammatory responses to Stx type 1 (Stx1) or Stx type 2 (Stx2) both in vivo and in vitro, none have examined dynamic immune regulation involving cytokines and/or unknown inflammatory mediators during intoxication. Here, we showed that enzymatically active Stxs trigger the dissociation of lysyl-tRNA synthetase (KRS) from the multi-aminoacyl-tRNA synthetase complex in human macrophage-like differentiated THP-1 cells and its subsequent secretion. The secreted KRS acted to increase the production of proinflammatory cytokines and chemokines. Thus, KRS may be one of the key factors that mediate transduction of inflammatory signals in the STEC-infected host.

• Fisheries and Aquatic Sciences
• /
• v.17 no.1
• /
• pp.155-158
• /
• 2014

The objective of this study was to evaluate the antiviral activity of Phaeophyta extracts against feline calicivirus (FCV), used as a norovirus surrogate. A bioassay-guided cytotoxicity and virus infectivity assay revealed that methanolic extracts of Phaeophyta possessed significant antiviral activity against FCV. Among them, Eisenia bicyclis extract exhibited the highest antiviral activity against FCV. The 50% effective concentration of the extract ($EC_{50}$) inhibiting FCV viral replication by 50% was $80{\mu}g/mL$. The extract also showed the highest selectivity index, calculated from the ratio of the median cellular cytotoxicity concentration ($CC_{50}$) and $EC_{50}$, indicating antiviral efficacy against FCV. In addition, significant interruption of FCV infection was observed by pretreatment of host Crandall-Reese feline kidney cells with the E. bicyclis extract ($200{\mu}g/mL$) prior to virus infection, in a dosedependent manner.

• Proceedings of the Korean Biophysical Society Conference
• /
• 2003.06a
• /
• pp.72-72
• /
• 2003

The PAS factor, whose gene has been cloned from V vulnifcus, is a protein secretion factor. Although the role of the PAS factor in Vibrio is still unknown, it may be involved with the bacterial protein secretion. The PAS factor is a 76 amino acid polypeptide, and its expression in E. coli cells makes the host cell membrane leaky, resulting in the excretion of periplasmic proteins into the culture medium. Highly expressed PAS factor is harmful to the cell, this may be due to a disruption of the membrane structure or function.

• Korean Journal of Veterinary Service
• /
• v.37 no.1
• /
• pp.35-43
• /
• 2014

Salmonellosis has caused heavy losses in swine industry and implications for public health. Recently, the urgent problem of antibiotic resistance due to multidrug-resistant Salmonella spp. has been on the rise. The use of host-specific bateriophages as a biocontrol is one possible alternative. In this study, clinical signs, growth performance, quantification and detection of antigen, histopathological changes of gastrointestinal tracts were analyzed comparatively in weaned piglets according to administration of bacteriophages and challenge with Salmonella (S.) Typhimurium. Piglets challenged with S. Typhimurium after administered with bacteriophages showed reduced clinical signs, higher growth performance, lower bacterial shedding, lower quantificational value of antigens in intestines, higher V/C ratio and higher the number of goblet cells in intestines than piglets administered without bacteriophage and challenged with S. Typhimurium. These results indicate that feeding contained with bacteriophages has effect to prevent infection of S. Typhimurium in weaned piglets and suggest that a use of bacteriophage can be considered a valid antibiotic alternative.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.8
• /
• pp.2466-2472
• /
• 2013

Human immunodeficiency virus type-1 (HIV-1) is a causative agent of Acquired immunodeficiency syndrome (AIDS), which has affected a large population of the world. Viral envelope glycoprotein (gp120) is an intrinsic protein for HIV-1 to enter into human host cells. Molecular docking guided molecular dynamics (MD) simulation was performed to explore the interaction mechanism of heterobiaryl derivative with gp120. MD simulation result of inhibitor-gp120 complex demonstrated stability. Our MD simulation results are consistent with most of the previous mutational and modeling studies. Inhibitor has an interaction with the CD4 binding region. Van der Waals interaction between inhibitor and Val255, Thr257, Asn425, Met426 and Trp427 were important. This preliminary MD model could be useful in exploiting heterobiaryl-gp120 interaction in greater detail, and will likely to shed lights for further utilization in the development of more potent inhibitors.

• The Korean Journal of Mycology
• /
• v.1 no.2
• /
• pp.31-33
• /
• 1973

On September 1972, a blight disease of turf (Arostis canina L.)was found in a golf link in Seoul Country Club at Seoul, Korea. Yellow circular patches of 15-20cm in diameter were observed and spreaded irregulary to collapse of themselves. The roots of the diseased plants were dark in color and were in a final state of decay. We isolated Curvularia sp. from the diseased plants and investigated the morphological and cultural characters. Its characters as follows: Mycelia septate, branched, hyaline or yellowish brown colored. Conidiophores septate, thin brown, unbranched. $65-270{\times}3.5-5{\mu}$. Conidia clustered at the tips of conidiophores, boat form or slightly curved with 1-5 septa, brown; both end cells hyaline; the third cell much larger than the others. $26.1-33.3{\times}9.5-10.1{\mu}$ (4 cell's conidium). The pathogenicity of the fungus to host plant was confirmed by soil inoculation method. We classified the fungus according to Gilman's method as a species Curvularia geniculata (Tracy and Earle) Boedjin.

• Molecules and Cells
• /
• v.27 no.2
• /
• pp.237-241
• /
• 2009

Pathogens Burkholderia pseudomallei (Bp) and Burkholderia mallei (Bm) contain a large number (> 12,000) of Simple Sequence Repeats (SSRs). To study the extent to which these features have contributed to the diversification of genes, we have conducted comparative studies with nineteen genomes of these bacteria. We found 210 genes with characteristic types of SSR variations. SSRs with nonamer repeat units were the most abundant, followed by hexamers and trimers. Amino acids with smaller and nonpolar R-groups are preferred to be encoded by the variant SSRs, perhaps due to their minimal impacts to protein functionality. A majority of these genes appears to code for surface or secreted proteins that may directly interact with the host factors during pathogenesis or other environmental factors. There also are others that encode diverse functions in the cytoplasm, and this protein variability may reflect an extensive involvement of phase variation in survival and adaptation of these pathogens.