• Preventive Nutrition and Food Science
• /
• 제15권1호
• /
• pp.74-77
• /
• 2010

Antibiotic-resistant Staphylococcus aureus is beginning to pose a social issue. Thus, there is an urgent need for the development of effective anti-staphylococcal agents to eradicate antibiotic-resistant S. aureus in food systems and to treat the pathogen in clinical areas. To address this need, lactic acid bacteria (LAB) from kimchi were screened for the production of anti-staphylococcal bacteriocin. From this screening, a bacteriocin generated by the MK3 strain, which was identified by 16S rRNA gene sequence analysis as Enterococcus faecium, demonstrated antimicrobial activity against an S. aureus strain, and was designated enterocin MK3. Enterocin MK3 also demonstrated activity against other gram-positive bacteria, including several LAB and Listeria monocytogenes, but not gram-negative Escherichia coli. The molecular mass of enterocin MK3 was estimated as approximately 6.5 kDa on an SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) gel.

• 대한의생명과학회지
• /
• 제20권2호
• /
• pp.96-102
• /
• 2014

Staphylococcal enterotoxin B (SEB) is bacterial toxin that induces the activation of immune cells. Because the inhibition of pro-inflammatory effect of SEB can resolve the inflammation, I determined the influence of functional or structural change of SEB on immune cells. The post translational modification of protein occurs through carbamylation. Carbamylation can change the structure of proteins and can modify the biological activity of protein. In the present study, I investigated the effect of carbamylated SEB (CSEB) on the inflammatory response mediated by LPS in HL-60 cells. To determine the anti-inflammatory effect of CSEB, I produced carbamylated SEB using potassium cyanate (KCN) and then examined whether CSEB involved in cytokine releases and apoptosis of LPS-stimulated HL-60 cells. Although CSEB had not any effect on the LPS-stimulated HL-60 cells, the protein levels of IL-8, TNF-${\alpha}$ and IL-$1{\beta}$ were significantly decreased by CSEB without cytotoxicity. CSEB also blocked Akt and NF-${\kappa}B$ activation. These results indicate that the suppressive effect of CSEB in LPS-stimulated cytokine releases is occurred by inhibition of Akt and NF-${\kappa}B$ activity. Through further studies, CSEB may be used as anti-inflammatory molecule that makes the immune system more efficient.

• 한국축산식품학회지
• /
• 제38권6호
• /
• pp.1315-1321
• /
• 2018

Bacteriocin is ribosomally synthesized by bacteria and inhibits closely related species. In this study we aimed at isolating lactic acid bacteria producing bacteriocin presenting anti-staphylococcal activity. A Lactococcus lactis strain was isolated from kimchi for the purpose and identified by 16S rRNA gene sequencing. As preliminary tests, optimal culture conditions, stabilities against heat, solvents, and enzymes treatments, and type of action (bacteriostatic or bactericidal) of the bacteriocin were investigated. The optimal culture conditions for production of the bacteriocin were MRS broth medium and $25^{\circ}C$ and $30^{\circ}C$ culture temperatures. The bacteriocin was acidic and the activity was abolished by a protease treatment. Its stability was maintained at $100^{\circ}C$ for 15 min and under treatments of various organic solvents such as methanol, ethanol, acetone, acetonitrile, and chloroform. Finally, the bacteriocin showed bactericidal action against Staphylococcus aureus where 200 AU/mL of the bacteriocin decreased the viable cell count (CFU/mL) of S. aureus by 2.5 log scale, compared with a control (no bacteriocin added) after 4-h incubation.

• Archives of Pharmacal Research
• /
• 제24권2호
• /
• pp.89-94
• /
• 2001

Several quaternary pyridinium cephalosporin analogues were prepared analogues were Prepared and evaluated in vitro for antibacterial activity against selected Gram-positive and Cram-negative organisms. Most of the synthesized analogues were either as effective or less effective against the tested bacterial organ isms than the reference com pounds, Cefpirome and Ceftazidime.

• Journal of Microbiology and Biotechnology
• /
• 제28권9호
• /
• pp.1426-1432
• /
• 2018

Staphylococcus aureus causes a broad variety of diseases. The spread of multidrug-resistant S. aureus highlights the need to develop new ways to combat S. aureus infections. Sortase A (SrtA) can anchor proteins containing LPXTG binding motifs to the bacteria surface and plays a key role in S. aureus infections, making it a promising antivirulence target. In the present study, we used a SrtA activity inhibition assay to discover that isovitexin, a Chinese herbal product, can inhibit SrtA activity with an $IC_{50}$ of $28.98{\mu}g/ml$. Using a fibrinogen-binding assay and a biofilm formation assay, we indirectly proved the SrtA inhibitory activity of isovitexin. Additionally, isovitexin treatment decreased the amount of staphylococcal protein A (SpA) on the surface of the cells. These data suggest that isovitexin has the potential to be an anti-infective drug against S. aureus via the inhibition of sortase activity.

• Journal of Microbiology and Biotechnology
• /
• 제22권6호
• /
• pp.800-805
• /
• 2012

Licochalcone E was firstly isolated from licorice root in 2005, which belongs to the retrochalcone family. Studies on the biological activities of licochalcone E were in the initial stage. In the study, we demonstrated that licochalcone E has potent antimicrobial property against Staphylococcus aureus. Furthermore, via hemolysis, Western blot, and real-time RT-PCR assays, we have shown that subinhibitory concentrations of licochalcone E dose-dependently reduces the production of ${\alpha}$-toxin in both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA). The data suggest that licochalcone E may deserve further investigation as a potential therapeutic against S. aureus infections, or the structure of licochalcone E may be used as a basis for chemical synthesis of novel anti-S. aureus compounds.

• KSBB Journal
• /
• 제20권3호
• /
• pp.228-232
• /
• 2005

본 연구에서는 우리나라 민속약이나 한방의 약재로 널리 사용되어 온 참쑥 (Artemisia mongolica fishcher)으로부터 추출한 쑥 추출물이 포도상구균 (Staphylococcu aurues)과 유산균 (Lactobacillus spp.)에 대해 선택적 저해 효과를 갖는지 조사하였다. 우선 항균 활성 실험을 통해 포도상구균을 저해하는 우수한 항균력을 가진 유산균 7균주를 선별하였다. 그리고 쑥을 추출한 용매의 종류, 농도 그리고 추출시간을 달리하여 쑥 추출물의 최적 농도 조건을 결정하였다. 생존율을 측정하기 위해 배양액에 각각 3일 동안 용매 $100\%$ (아세톤, 에탄올, 메탄올)로 추출한 쑥 추출물을 $17\%$ 첨가하였고, 이때 항균 활성 있는 유산균 KLB 224은 배양 48시간까지 생존하였다. 그러나 포도상구균은 동일한 조건에서 모두 사멸되었다. 또한 주사전자현미경 관찰을 통해 쑥 추출물이 세포 형태에 미치는 영향을 확인하였다. 그 결과, 포도상구균은 세포 형태가 심하게 손상되었지만 유산균은 저해를 받지 않고 세포형태를 유지함을 관찰하였다.