• 제목/요약/키워드: Antibacterial mechanism

검색결과 108건 처리시간 0.023초

Photodynamic Therapy for Methicillin-resistant Staphylococcus aureus Strain using Photogem and 630 nm LED

  • 안진철
    • 대한의생명과학회지
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    • 제14권4호
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    • pp.269-274
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    • 2008
  • Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common nosocomial pathogens. It is associated with hospitals is now being isolated in the community. The aim of this study was to evaluate the antibacterial effect of photodynamic therapy using Photogem and 630 nm LED on MRSA and methicillin-sensitive Staphylococcus aureus (MSSA). The broth cultured MRSA and MSSA incubated with various concentrations of Photogem (500,50,5 and $0.5{\mu}g/mL$) for 4 h. Then 630 nm LED was given at $9\;J/cm^2$, $20{\mu}l$ of the exposed bacteria solution was inoculated onto agar plate. Plates were incubated for 24 hand colonies were counted. The PDT group was effective in killing MRSA and MSSA at the Photogem dose of $50{\mu}g/mL$. But MSSA is more sensitive than MRSA in photodynamic effect. Other groups (light only, sensitizer only, or no treatment) observed no bacterial cell killing. These results raise the possibility of using PDT with or without antimicrobial drugs to eradicate MRSA and MSSA. In order to confirm this result, we need to further study bacterial death mechanism and in vivo study.

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소리쟁이(Rumex crispus) 추출물의 제1형 알레르기 반응 억제 효과 (Rumex crispus Suppresses Type I Hypersensitive Immune Response)

  • 고은교;김영미
    • 생약학회지
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    • 제50권4호
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    • pp.277-284
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    • 2019
  • Rumex crispus is known to have anticancer, antioxidant, antibacterial, and bone loss inhibitory activities. Mast cells are critical immune cells that induce a type 1 IgE-mediated allergic reaction. However, there are no reports of inhibitory effects of Rumex crispus on mast cells and allergic reactions. In this study, we performed some experiments to investigate whether Rumex crispus ethanol extract(RCE) has any inhibitory effect on antigen-induced type I allergic response in vitro and in vivo. RCE inhibited degranulation of IgE-mediated mast cells(IC50, ~57 ㎍/ml) and cytokine production such as TNF-α and IL-4 in a dose-dependent manner. In vivo, RCE significantly inhibited passive cutaneous anaphylaxis(PCA)(ED50, ~198 mg/kg) in mice. Furthermore, RCE inhibited degranulation of MCs in ear tissue of mice with PCA. Mechanism studies showed that RCE inhibited the activation of Syk and Syk-dependent pathway such as LAT, PLC-γ, Akt, and MAP Kinase. Our results demonstrate for the first time that RCE inhibits type I hypersensitive response by suppressing the activity of Syk in mast cells, thereby reducing degranulation and cytokine production. Taken together, RCE could be used as a novel therapeutic material to suppress allergic diseases.

Ethyl linoleate inhibits α-MSH-induced melanogenesis through Akt/GSK3β/β-catenin signal pathway

  • Ko, Gyeong-A;Kim Cho, Somi
    • The Korean Journal of Physiology and Pharmacology
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    • 제22권1호
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    • pp.53-61
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    • 2018
  • Ethyl linoleate is an unsaturated fatty acid used in many cosmetics for its various attributes, such as antibacterial and anti-inflammatory properties and clinically proven to be an effective anti-acne agent. In this study, we investigated the effect of ethyl linoleate on the melanogenesis and the mechanism underlying its action on melanogenesis in B16F10 murine melanoma cells. Our results revealed that ethyl linoleate significantly inhibited melanin content and intracellular tyrosinase activity in ${\alpha}$-MSH-induced B16F10 cells, but it did not directly inhibit activity of mushroom tyrosinase. Ethyl linoleate inhibited the expression of microphthalmia-associated transcription factor (MITF), tyrosinase, and tyrosinase related protein 1 (TRP1) in governing melanin pigment synthesis. We observed that ethyl linoleate inhibited phosphorylation of Akt and glycogen synthase kinase $3{\beta}$ ($GSK3{\beta}$) and reduced the level of ${\beta}-catenin$, suggesting that ethyl linoleate inhibits melanogenesis through $Akt/GSK3{\beta}/{\beta}-catenin$ signal pathway. Therefore, we propose that ethyl linoleate may be useful as a safe whitening agent in cosmetic and a potential therapeutic agent for reducing skin hyperpigmentation in clinics.

Identification of An Antibacterial Gene by Differential Display from Lipopolysaccharide-Stimulated Dung Beetle, Copris tripartitus

  • Suh, Hwa-Jin;Kim, Yeon-Ju;Bang, Hea-Son;Yun, Eun-Young;Kim, Seong-Ryul;Park, Kwan-Ho;Kang, Bo-Ram;Kim, Ik-Soo;Jeon, Jae-Pil;Hwang, Jae-Sam
    • International Journal of Industrial Entomology and Biomaterials
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    • 제17권2호
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    • pp.223-228
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    • 2008
  • A novel beetle antimicrobial protein from stimulated Copris tripartitus and the corresponding gene were isolated in parallel through differential display-PCR and expression in Escherichia coli. To find cDNA clones responsible for bacteria resistance, the suppression subtractive hybridization and GeneFishing differentially expressed genes system were employed in the dung beetle, Copris tripartitus immunized with lipopolysaccaride. One cDNA clone from eight subtracted clones was selected through dot blot analysis and confirmed by northern blot analysis. The 516-bp, selected cDNA clone was determined by 5' and 3' rapid amplication of cDNA ends and cloned into the GST fusion expression vector pGEX-4T-1 for expression of the protein. The expressed protein was predicted 14.7 kDa and inhibited the growth of gram-negative bacteria such as Escherichia coli and Pseudomonas aeruginosa. These results implied that the expressed protein is related to immune defense mechanism against microorganism.

Baicalin이 조골세포의 생성 및 활성에 미치는 영향 (Effects of Baicalin on the Proliferation and Activity of Osteoblastic Cells)

  • 고선일
    • Journal of Oral Medicine and Pain
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    • 제33권2호
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    • pp.105-110
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    • 2008
  • Baicalin은 Scutellaria baicalensis에서 분리되는 flavonoid의 일종으로, 다양한 생물학적 활성을 나타내는 물질로 알려져 있다. Baicalin은 항균, 항염증, 진통작용을 나타내며, nuclear factor-kappaB의 활성을 억제한다고 보고되었다. 최근에 다양한 flavonoid 들이 골조직 대사에 관여함이 밝혀졌으며, 본 연구에서는 baicalin이 골조직의 주요세포인 조골세포의 생성 및 활성에 미치는 영향을 관찰하기 위하여, 세포증식율, 세포생존율, 염기성 인산분해효소 활성 및 osteoprotegerin 생성량의 변화를 관찰하였다. 그 결과 baicalin은 조골세포의 세포 증식과 생존율에는 영향을 미치지 못하였으나, 염기성 인산분해효소의 활성과 osteoprotegerin의 생성량을 증가시켰다. 따라서 baicalin은 골조직에서 조절물질로 역할을 할 것으로 예견된다.

Beneficial Effects of Lactobacillus casei ATCC 334 on Halitosis Induced by Periodontopathogens

  • Lee, Ki-Ho;Baek, Dong-Heon
    • International Journal of Oral Biology
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    • 제39권1호
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    • pp.35-40
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    • 2014
  • Halitosis is caused by consumption of certain foods or drinks and production of volatile sulfur compounds (VSCs) by periodontopathogens. VSCs-related halitosis is not easily removed using mechanical or chemical therapies such as dental floss, plaque control and mouth rinse. Lactobacillus are known to be probiotics and stimulate immune systems of human. Furthermore, L. casei ATCC 334 and L. rhamnosus GG have an effect on protection of dental caries in vitro studies. The aim of this study was to investigate effect of Lactobacillus on halitosis by Fusobacterium nucleatum- and Porphyromonas gingivalis-producing VSCs and to analyze inhibitory mechanism. The periodontopathogens were cultivated in the presence or the absence Lactobacillus, and the level of VSCs was measured by gas chromatograph. For analysis of inhibitory mechanisms, the susceptibility assay of the spent culture medium of Lactobacillus against F. nucleatum and P. gingivalis was investigated. Also, the spent culture medium of Lactobacillus and periodontopathogens were mixed, and the emission of VSCs from the spent culture medium was measured by gas chromatograph. L. casei and L. rhamnosus significantly reduced production of VSCs. L. casei and L. rhamnosus exhibited strong antibacterial activity against F. nucleatum and P. gingivalis. The spent culture medium of L. casei inhibited to emit gaseous hydrogen sulfide, methyl mercaptan and dimethyl sulfide from the spent culture medium of periodontopathogens. However, the spent medium of L. rhamnosus repressed only dimethyl sulfide. L. casei ATCC 334 may improve halitosis by growth inhibition of periodontopathogens and reduction of VSCs emission.

Comparison of the Sensitivity of Type I Signal Peptidase Assays

  • Sung, Meesook
    • Journal of Life Science
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    • 제11권2호
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    • pp.94-98
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    • 2001
  • Type I signal peptidase cleaves the signal sequence from the amino terminus of membrane and secreted proteins afters these protein insert across the membrane. This enzyme serves as a potential target for the development of novel antibacterial agents due to its unique physiological and biochemical properties. Despite considerable research, the signal peptidase assay still remains improvement to provide further understanding of the mechanism and high-throughput inhibitor screening of this enzyme. In this paper, three known signal peptidase assays are tested with an E. coli D276A mutant signal peptidase to distinguish the sensitivity of each assays. In vitro assay using the procoat synthesized by in vitro transcription translation shows that the D276A signal peptidase I was inactive while in vivo processing of pro-OmpA expressed in the temperature-sensitive E. coli strain IT41 as well as in vitro assay using pro-OmpA nuclease A substrate show that D276A signal peptidase I has activity like wild-type signal peptidase. These results suggest that in vitro assay using the pro-OmpA nuclease A and in vivo pro-OmpA processing assay are more sensitive monitors than in vitro assay using the pro-coat. In conculsion, caution should be used when interpreting the in vitro results using the procoat.

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Norfloxacin Resistance Mechanism of E. coli 11 and E. coli 101-Clinical Isolates of Escherichia coli in Korea

  • Kim, Kyung-Soon;Lee, Soon-Deuk;Lee, Yeon-Hee
    • Archives of Pharmacal Research
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    • 제19권5호
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    • pp.353-358
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    • 1996
  • E. coli 11 and E. coli 101, clinical isolates of Escherichia coli were resistant to various quinolones, especially MICs to norfloxacin of both strains were higher than 100 mg/ml. In the presence of carbonyl cyanide m-chlorophenylhydrazone, a proton gradient uncoupler, norfloxacin uptake in both strains was increased, suggesting that an efflux system play an important role in the norfloxacin resistance. Outer membrane proteins of the susceptible and resistant strains which could affect the route of norfloxacin entry into cells were different. When quinolone resistance determining region(QRDR) of gyrA was amplified using PCR and cut with Hinf I, QRDR in the susceptible strain yielded two fragments while QRDRs in E. coli 11 and E. coli 101 yielded only one uncut fragment. When DNA sequence of QRDR was analyzed, there were two mutations as Ser-83 and Asp-87 in both resistant strains. these residues were changed to Leu-83 and Asn-87, respectively. These results showed that the norfloxacin resistance of E. coli 11 and E. coli 101 was resulted from multiple changes-an altered DNA gyrase A subunit, a change in route of drug entry, and reduction in quinolone concentration inside cells due to an efflux system.

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백서 기관 및 후두에서 분비조직의 발생 (Development of Secretory Element in Murine Trachea and Larynx)

  • 조정일;박기현;김광문
    • 대한기관식도과학회:학술대회논문집
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    • 대한기관식도과학회 1993년도 제27차 학술대회 초록집
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    • pp.67-67
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    • 1993
  • 기관 및 후두의 점막표면은 중이나 이관과 마찬가지로 점막섬모 정화작용, 면역글로린, 항세균 효소 등의 다양한 점막 방어기전에 의해 보호되고 있는데 기관 및 후두의 분비선과 분비세포의 형태에 관한 보고는 많으나 분비활성도와 연관된 분비조직의 발생에 대한 연구는 충분치 못하다. 저자들은 백서 기관 및 후두의 분비조직의 발생을 알아보고 향후 기관 및 후두의 발생형태학적 연구의 기초자료로 삼기 위해서 임신 16일부터 생후 21사이의 백서를 이용하여 H & E 염색, AB-PAS 염색과 lysozyme의 면역조직화학적 방법을 통하여 백서 기관 및 후두분비조직의 발달을 연구하였다. 그 결과 백서 기관 및 후두의 분비기능은 출생후 폐의 통기와 함께 활성화되는 것으로 해석되었다.

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The Molecular Mechanism of Baicalin on RANKL-induced Osteoclastogenesis in RAW264.7 Cells

  • Ko, Seon-Yle
    • International Journal of Oral Biology
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    • 제38권2호
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    • pp.67-72
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    • 2013
  • This study examined the anti-osteoclastogenic effects of baicalin on receptor activator of NF-${\kappa}$B ligand (RANKL)-induced RAW264.7 cells. Baicalin is a flavonoid that is produced by Scutellaria baicalensis and is known to have multiple biological properties, including antibacterial, anti-inflammatory and analgesic effects. The effects of baicalin on osteoclasts were examined by measuring 1) cell viability; 2) the formation of tartrate-resistant acid phosphatase (TRAP) (+) multinucleated cells; 3) RANK/RANKL signaling pathways and 4) mRNA levels of osteoclast-associated genes. Baicalin inhibited the formation of RANKL-stimulated TRAP (+) multinucleated cells and also suppressed the RANKL-stimulated activation of p-38, ERK, cSrc and AKT signaling. Baicalin also inhibited the RANKL-stimulated degradation of $I{\kappa}B$ in RAW264.7 cells. In addition, the RANKL-stimulated induction of NFATc1 transcription factors was found to be abrogated by this flavonoid. Baicalin was further found to decrease the mRNA expression of osteoclast-associated genes, including carbonic anhydrase II, TRAP and cathepsin K in the RAW264.7 cells. Our data thus demonstrate that baicalin inhibits osteoclastogenesis by inhibiting the RANKL-induced activation of signaling molecules and transcription factors in osteoclast precursors.