• BMB Reports
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• v.34 no.1
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• pp.15-20
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• 2001

One of the innate immune reactions in invertebrates is the pro-phenoloxidase (pro-PO) activation system that is involved in the generation of superoxide, melanin synthesis, and the subsequent sequestration of foreign matter entering the hemocoel of the invertebrates. However, the molecular mechanism of this biological reaction is still obscure. To expand our understanding of the biological roles of the pro-PO activation system in invertebrates, we performed a yeast two-hybrid screening by using three regions of pro-PO as bait and a yeast two-hybrid cDNA library from Tenebrio molitor larvae as prey We isolated a novel partial cDNA clone that encodes a glycine-rich protein that interacted with the active phenoloxidase (termed phenoloxidase interacting protein, POIP). POIP consists of two domains: One is an N-terminal unique domain and the other is a C-terminal glycine-rich domain. The C-terminal glycine-rich domain showed sequential homology with those of insect antifungal proteins. Also, the yeast two-hybrid screen in a reverse orientation (using POIP as bait) yielded PO, suggesting that the PO-POIP interaction is specific. By using a 315 bP PCR fragment of the N-terminal unique region of POIP, we cloned the full-length cDNA of POIP from the Tenebruo cDNA library constructed by using E. coli injected larvae. The interaction analysis between PO, and a truncated fragment lacking the N-terminal unique region of POIP, indicated that the N-terminal unique region is necessary for interaction between PO and POIP. The expression level of the POIP mRNA is increased by bacterial injection into T. molitor larvae. This suggests that POIP might be engaged in the humoral defense reaction.

• Journal of Microbiology and Biotechnology
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• v.28 no.3
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• pp.482-490
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• 2018

Candida albicans infections are often problematic to treat owing to antifungal resistance, as such infections are mostly associated with biofilms. The ability of C. albicans to switch from a budding yeast to filamentous hyphae and to adhere to host cells or various surfaces supports biofilm formation. Previously, the ethanol extract from Paeonia lactiflora was reported to inhibit cell wall synthesis and cause depolarization and permeabilization of the cell membrane in C. albicans. In this study, the P. lactiflora extract was found to significantly reduce the initial stage of C. albicans biofilms from 12 clinical isolates by 38.4%. Thus, to assess the action mechanism, the effect of the P. lactiflora extract on the adhesion of C. albicans cells to polystyrene and germ tube formation was investigated using a microscopic analysis. The density of the adherent cells was diminished following incubation with the P. lactiflora extract in an acidic medium. Additionally, the P. lactiflora-treated C. albicans cells were mostly composed of less virulent pseudohyphae, and ruptured debris was found in the serum-containing medium. A quantitative real-time PCR analysis indicated that P. lactiflora downregulated the expression of C. albicans hypha-specific genes: ALS3 by 65% (p = 0.004), ECE1 by 34.9% (p = 0.001), HWP1 by 29.2% (p = 0.002), and SAP1 by 37.5% (p = 0.001), matching the microscopic analysis of the P. lactiflora action on biofilm formation. Therefore, the current findings demonstrate that the P. lactiflora ethanol extract is effective in inhibiting C. albicans biofilms in vitro, suggesting its therapeutic potential for the treatment of biofilm-associated infections.

• Biomolecules & Therapeutics
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• v.28 no.4
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• pp.370-379
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• 2020

Econazole, a potent broad-spectrum antifungal agent and a Ca²⁺ channel antagonist, induces cytotoxicity in leukemia cells and is used for the treatment of skin infections. However, little is known about its cytotoxic effects on solid tumor cells. Here, we investigated the molecular mechanism underlying econazole-induced toxicity in vitro and evaluated its regulatory effect on the metastasis of gastric cancer cells. Using the gastric cancer cell lines AGS and SNU1 expressing wild-type p53 we demonstrated that econazole could significantly reduce cell viability and colony-forming (tumorigenesis) ability. Econazole induced G0/G1 phase arrest, promoted apoptosis, and effectively blocked proliferation- and survival-related signal transduction pathways in gastric cancer cells. In addition, econazole inhibited the secretion of matrix metalloproteinase- 2 (MMP-2) and MMP-9, which degrade the extracellular matrix and basement membrane. Econazole also effectively inhibited the metastasis of gastric cancer cells, as confirmed from cell invasion and wound healing assays. The protein level of p53 was significantly elevated after econazole treatment of AGS and SNU1 cells. However, apoptosis was blocked in econazole-treated cells exposed to a p53-specific small-interfering RNA to eliminate p53 expression. These results provide evidence that econazole could be repurposed to induce gastric cancer cell death and inhibit cancer invasion.

• Journal of Microbiology and Biotechnology
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• v.15 no.2
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• pp.274-280
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• 2005

A chitinase was purified from the culture supernatant of Paenibacillus illinoisensis KJA-424 by protein precipitation, DEAE-Sephadex anion-exchange chromatography, and Sephadex G-150 gel filtration. The molecular weight of the purified chitinase was 54 kDa on SDS-PAGE and activity staining. Optimal pH and temperature were pH 5.0 and 60$^{circ}$C, the presence of 10 ruM Ag$^{+}$ and Hg$^{2+}$ inhibited the activity by $92.1/%$ and $97.7/%$, and the K$_{m}$ and V$_{max}$ values were 1.12 mg chitin mrl and 1.48$\mu$mol GlcNAc min$^{-1}$, respectively. The enzyme hydrolyzed tetramer to dimer, pentamer to dimer and trimer, and hexamer to dimer, trimer and tetramer, indicating an endo-splitting mechanism. The chitinase had no hydrolytic activity toward dimer and trimer. The chitinase inhibited the mycelial growth of Rhizoctonia solani, suggesting an antifungal property.

• The Korean Journal of Pain
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• v.25 no.1
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• pp.1-6
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• 2012

Background: Curcumin has been reported to have anti-inflammatory, antioxidant, antiviral, antifungal, antitumor, and antinociceptive activity when administered systemically. We investigated the analgesic efficacy of intrathecal curcumin in a rat model of inflammatory pain. Methods: Male Sprague Dawley rats were prepared for intrathecal catheterization. Pain was evoked by injection of formalin solution (5%, $50{\mu}l$) into the hind paw. Curcumin doses of 62.5, 125, 250, and $500{\mu}g$were delivered through an intrathecal catheter to examine the flinching responses. The $ED_{50}$ values (half-maximal effective dose) with 95% confidence intervals of curcumin for both phases of the formalin test were calculated from the dose-response lines fitted by least-squares linear regression on a log scale. Results: In rats with intrathecal administration of curcumin, the flinching responses were significantly decreased in both phases. The slope of the regression line was significantly different from zero only in phase 2, and the $ED_{50}$ value (95% confidence interval) of curcumin was $511.4{\mu}g$ (23.5-1126.5). There was no apparent abnormal behavior following the administration of curcumin. Conclusions: Intrathecal administration of curcumin decreased inflammatory pain in rats, and further investigation to elucidate the precise mechanism of spinal action of curcumin is warranted.

• Journal of Ginseng Research
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• v.38 no.3
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• pp.215-219
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• 2014

Background: Biological control of plant pathogens using benign or beneficial microorganisms as antagonistic agents is currently considered to be an important component of integrated pest management in agricultural crops. In this study, we evaluated the potential of Bacillus subtilis strain HK-CSM-1 as a biological control agent against Colletotrichum panacicola. Methods: The potential of B. subtilis HK-CSM-1 as a biological control agent for ginseng anthracnose was assessed. C. panacicola was inoculated to ginseng plants and the incidence and severity of disease was assessed to examine the efficacy of the bacterium as a biological control against C. panacicola. Results: Inoculation of Panax ginseng plants with B. subtilis significantly suppressed the number of disease lesions of C. panacicola and was as effective as the chemical fungicide iminoctadine tris(albesilate). The antifungal activity of B. subtilis against C. panacicola was observed on a co-culture medium. Interestingly, treatment with B. subtilis did not significantly affect the diameter of the lesions, suggesting that the mechanism of protection was through the reduction in the incidence of infection related to the initial events of the infection cycle, including penetration and infection via spore germination and appressorium formation rather than by the inhibition of invasive growth after infection. Conclusion: Our results suggest that B. subtilis HK-CSM-1 can be used as an effective and ecologically friendly biological control agent for anthracnose in P. ginseng.

• YAKHAK HOEJI
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• v.49 no.2
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• pp.140-146
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• 2005

Candida albicans, a polymorphic fungus, causes systemic and local infections. Recent reports show that the fungus is a main etiological agent for the arthritis. For trea tment, antifungal drugs and/or rheumatoid drugs are used, but resistance and side effects limit application of the drugs. In search of new sources for treatment of the fungal arthritis, we choose Egb 761 (extract of Ginkgo leaves 761), one of the most popular over-the-counter herbal medicines. The Egb 761 contains two major ingredients such as terpene and flavonoid. In the present study, we examined if the terpene portion of Egb 761 had anti-inflammatory activity against C.albicans-caused arthritis. The terpene was extracted with combination of methanol and water from the Egb 761, followed by gel-permeation chromatography. Presence of terpene was determined by the Salkowski colorimetric method and HPLC analysis. For an animal model of inflammation induction, mice were given an emulsion form of C.albicans cell wall mixed with Complete Freund's Adjuvant (CFA) by footpad-injection. Results showed that intraperitoneal administration of the water-soluble portion that contained terpene and flavonoid reduced the inflammation. Whereas the terpene had anti-inflammatory activity, flavonoid portion had no such activity, For determination of possible mechanism of the activity, the terpene seemed to be suppression of nitric oxide (NO) production from LPS-treated macrophages. Taken together the Ginkgo terpene may have anti-inflammatory effect against C.albicans-caused arthritis, possibly by blocking NO production.

• Journal of Microbiology and Biotechnology
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• v.18 no.5
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• pp.828-836
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• 2008

The biocontrol rhizobacterium Pseudomonas sp. M18 can produce two kinds of antibiotics, namely pyoluteorin (Plt) and phenazine-1-carboxylic acid (PCA), and is antagonistic against a number of soilborne phytopathogens. In this study, a luxR-type quorum-sensing regulatory gene, vqsR, was identified and characterized immediately downstream of the Plt gene cluster in strain MI8. A vqsR-inactivated mutant led to a significant decrease in the production of Plt and its biosynthetic gene expression. However, this was restored when introducing the vqsR gene by cloning into the plasmid pME6032 in trans. The vqsR mutation did not exert any obvious influence on the production of PCA and its biosynthetic gene expression and the production of N-acylhomoserine lactones (C4 and C8-HSLs) and their biosynthetic gene rhlI expression. Accordingly, these results introduce VqsR as a regulator of Plt production in Pseudomonas spp., and suggest that the regulatory mechanism of vqsR in strain M18 is distinct from that in P. aeruginosa. In addition, it was demonstrated that vqsR mutation did not have any obvious impact on the expression of Plt-specific ABC transporters and other secondary metabolic global regulators, including GacA, RpoS, and RsmA.

• Korean Journal of Microbiology
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• v.54 no.3
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• pp.175-187
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• 2018

Myxobacteria produce diverse secondary metabolites for predation, self-defense, intercellular signaling, and other unknown functions. Many secondary metabolites isolated from myxobacteria show pharmaceutically useful bioactivity such as anticancer, antibacterial, and antifungal activities with a unique mechanism of action. Therefore, a large number of myxobacterial strains have been isolated globally and many bioactive compounds have been purified from them. However, 16S rRNA database analysis indicates that there are far more types of myxobacterial species in the wild than have ever been isolated, and genome sequence analysis suggests that each myxobacterium is capable of producing much more metabolites than already known. In this article, the current status of studies on the secondary metabolites from myxobacteria, their biosynthetic genes, biological functions, and transcriptional regulatory factors governing gene expression were reviewed.

• International Journal of Oral Biology
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• v.46 no.2
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• pp.85-93
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• 2021

Asarum sieboldii Miq. (Aristolochiaceae) is a perennial herbaceous plant and has been used as traditional medicine for treating diseases, cold, fever, phlegm, allergies, chronic gastritis, and acute toothaches. Also, it has various biological activities, such as antiallergic, antiinflammatory, antinociceptive, and antifungal. However, the anticancer effect of A. sieboldii have been rarely reported, except anticancer effect on lung cancer cell (A549) of water extracts of A. sieboldii. This study investigated the anticancer activity of methanol extracts of A. sieboldii (MeAS) and the underlying mechanism in human FaDu hypopharyngeal squamous carcinoma cells. MeAS inhibited FaDu cells grown dose-dependently without affecting normal cells (L929), as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and live and dead assay. In addition, concentration of MeAS without cytotoxicity (0.05 and 0.1 mg/mL) inhibited migration and colony formation. Moreover, MeAS treatment significantly induced apoptosis through the proteolytic cleavage of caspase-3, -7, -9, poly (ADP-ribose) polymerase, and downregulation of Bcl-2 and upregulation of Bax in FaDu cells, as determined by fluorescence-activated cell sorting analysis, 4'6-diamidino-2-phenylindole stain, and western blotting. Altogether, these results suggest that MeAS exhibits strong anticancer effects by suppressing the growth of oral cancer cells and the migration and colony formation via caspase- and mitochondrial-dependent apoptotic pathways in human FaDu hypopharyngeal squamous carcinoma cells. Therefore, MeAS can serve as a natural chemotherapeutic for human oral cancer.