• Bulletin of the Korean Chemical Society
• /
• v.30 no.8
• /
• pp.1873-1876
• /
• 2009

• Archives of Pharmacal Research
• /
• v.22 no.1
• /
• pp.25-29
• /
• 1999

Psammaplin A, a natural bromotyrosine derivative from an associated form of two sponges (Poecillastra sp. and jaspis sp.) was found to possess the antimicrobial effect on the Gram-positive bacteria, especially on methicillin-resistant Staphylococcus aureus (MRSA). The minimal inhibitory concentration of psammaplin A against twenty one MRSAs ranged from 0.781 to 6.25 ${\mu}g/ml$, which that of ciprofloxacin was 0.391~3.125${\mu}g/ml$. Psammaplin A could not bind to penicillin binding protein, but inhibited the DNA synthesis and the DNA gyrase activity with the respective 50% (DNA synthesis) and 100% (DNA gyrase) inhibitory concentration 2.83 and 100 ${\mu}g/ml$. These results indicate that psammaplin A has a considerable antibacterial activity, although restricted to a somewhat narrow range of bacteria, probably by inhibiting DNA gyrase.

• KSBB Journal
• /
• v.27 no.1
• /
• pp.9-15
• /
• 2012

Antimicrobial peptides are widely used in various organisms as a defense system against infection. The peptides are lethal towards bacteria and fungi, however have minimal toxicity in mammalian and plant cells. In this aspect, it is considered that antimicrobial peptides are new alternative materials for defensing against microbial infection. Here, we describe overall characteristics of antimicrobial peptides based on the mechanism of action, classification of the peptides, report detection/screening methods and chemical/biological production. It is expected that understanding of innate immune system based on antimicrobial peptides tends to develop novel natural antimicrobial agents, which might be applied for defensing pathogenic microorganisms resistant to conventional antibiotics.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 1993.08a
• /
• pp.24-30
• /
• 1993

• Proceedings of the PSK Conference
• /
• 2000.04a
• /
• pp.122.1-122.1
• /
• 2000

• Animal cells and systems
• /
• v.10 no.4
• /
• pp.227-231
• /
• 2006

Micro-deletions at specific loci of the Y chromosome have been observed frequently in male infertility patients, suggesting that genes in these regions are involved in male germ cell development. DAZ is a representative male infertility gene at the AZFc locus of the Y chromosome. Since DAZ contains an RNA binding motif along with so-called a DAZ domain, it was proposed to participate in RNA metabolism during spermatogenesis. A mouse gene homologous to the human DAZ gene has been cloned and named Dazl (DAZlike). Dazl is autosomal and expressed in the testis and also at a low level in the ovary. Male mice homozygous for the Dazl null allele have small testes with a few spermatogonia and almost complete absence of germ cells beyond the spermatogonial stage, suggesting the requirement of Dazl for entry or progression through meiosis. However, its exact cellular functions have not been understood yet. In order to investigate cellular functions of Dazl, we decided to isolate candidate interacting protein genes of the mouse Dazl, using yeast two-hybrid screening. A number of candidate Dazlinteracting proteins have been isolated, such as Bprp, Acf, Hgs, Murr1, Nbak3 and Ranbp9, but dynein light chain 1 (Dlc1) was most predominant. A strong interaction of Dazl with Dlc1 suggests that Dazl might function as an mRNA adaptor to the dynein motor complex.

• Natural Product Sciences
• /
• v.20 no.3
• /
• pp.170-175
• /
• 2014

Twenty five methanolic plant extracts were investigated to determine the anticancer activity against sonic hedgehog (shh)/Gli signaling pathway dependent cancer, PANC-1 human pancreatic cancer cells, through three screening programs. All extracts were inspected their inhibitory properties on sonic hedgehog-conditioned medium (shh-CM) induced alkaline phosphatase (ALP) activity in C3H10T1/2 mouse mesenchymal stem cells to examine whether the plant extracts affect the shh/Gli signaling pathway. Next, plant extracts were screened the ability to suppress the cell proliferation of PANC-1 human pancreatic cancer cells. Finally, active plant extracts from the two screening systems were evaluated for the suppressive effect on Gli-mediated transcriptional activity in PANC-1 cells. Among active plants, Cinnamomum cassia suppressed Gli-mediated transcriptional activity leading to the down-regulated expression of Gli-target genes such as Gli-1 and Patched-1 (Ptch-1). This study provides the consideration for the important role of natural products in drug discovery process as well as the basis for the further analysis of active plant and potential identification of novel bioactive compounds as inhibitors of Gli and therapeutic candidates against shh/Gli signaling pathway dependent cancers.

• Korean Journal of Pharmacognosy
• /
• v.28 no.4
• /
• pp.286-292
• /
• 1997

We studied the screening condition for immune regulatory responsor. We focused on the T-lymphocytes leer this purpose. Mouse fetal thymic organ culture (FTOC) system and flow cytometric analysis were mainly used in this experiment. Even if FTOC is carried out in vivo condition, the pattern of thymic development in the condition of FTOC is similar to that of in vivo condition. In this regard, FTOC system might be very powerful tool to screen the immune regulator, especially concerning on T cells. To establish the optimum condition of FTOC to screen the Immune regulator, we focused on the optimum amount of dose and culture period. The cell number and surface antigens on T cells were also analysed by using hemacytometer and flow cytometer. To monitor the differentiation event, anti-CD3, anti-CD4 and anti-CD8 antibodies were used. Alkoxyglycerol and Phellodendri Cortex were used fur positive and negative control, respectively. Astragalus membranceus was used as test sample. From our analysis, we reached to conclusions that the best dose of extract is $50\;{\mu}g/ml$ of culture medium, the best culture period is for 9 days, and ethanol used as solvent has no toxicity to FTOC.

• Korean Journal of Plant Resources
• /
• v.6 no.1
• /
• pp.25-32
• /
• 1993

Many plants, which collected from Korea, were applied to antitumor and cytotoxic screeing tests against sarcom 180 a ascitec in mice, V-79 KB and P388 cultured cells. The results are summarixed as follows:1) The total packed cell volum method has been used for the antineoplastic screening for from natural higher plants in Korea. By this method, we have found out that the root, leaf and stem of Tripterygiu, regelii Spragne & Taketa having strong antineoplastic activity and also Rumex Japonicus Houtt. Eragrositis ferru-ginea Beauv. and Patrinia scabio-saefolia Fischer showed significant activity to anticancer tumor while cynanchum wilfordii Hemsley, and Rosa polyantha Sieb. et Zacc. showed slight activity to antitumor. 2) Among the 13 tested plants, the root and stem of Tripterygium regelii Spragne & Taketa and Amethystanthus excisus Nakai showed strong antitumor activity by the V79 cytotoxic cell screening test. 3) Twelve plants, which are glowing in mountainous area of Korea tested to anticancer activity. From the results, Eragrositis ferru-ginea Beauv., Angelica gigas Nakai, Geranium sibiricum L., Patrinia scabio-saefolia Fisher, Cynanchum wilfordii Hemsley, and Rubia akane Nakai have been proved to be anti-cancer plants by using P388 cell cultured method. 4) Tripterygiu, resgelii Spragne & Taketa, Eragrositis ferru-ginea Beauv., Patrinia scabio-saefoli Fisher, Cynanchum wilfordii Hemsley and Rasa polyantha Sieb. et Zacc., var. genuina Thunb. showed strong anti-tumor activity both total packed cell volume method and Cytotoxicity method.

• Biomolecules & Therapeutics
• /
• v.30 no.5
• /
• pp.427-434
• /
• 2022

The drug repurposing strategy has been applied to the development of emergency COVID-19 therapeutic medicines. Current drug repurposing approaches have been directed against RNA polymerases and viral proteases. Recently, we found that the inhibition of the interaction between the SARS-CoV-2 structural nucleocapsid (N) and spike (S) proteins decreased viral replication. In this study, drug repurposing candidates were screened by in silico molecular docking simulation with the SARS-CoV-2 structural N protein. In the ChEMBL database, 1994 FDA-approved drugs were selected for the in silico virtual screening against the N terminal domain (NTD) of the SARS-CoV-2 N protein. The tyrosine 109 residue in the NTD of the N protein was used as the center of the ligand binding grid for the docking simulation. In plaque forming assays performed with SARS-CoV-2 infected Vero E6 cells, atovaquone, abiraterone acetate, and digoxin exhibited a tendency to reduce the size of the viral plagues without affecting the plaque numbers. Abiraterone acetate significantly decreased the accumulation of viral particles in the cell culture supernatants in a concentration-dependent manner. In addition, abiraterone acetate significantly decreased the production of N protein and S protein in the SARS-CoV-2-infected Vero E6 cells. In conclusion, abiraterone acetate has therapeutic potential to inhibit the viral replication of SARS-CoV-2.