Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 12

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  Porphyromonas gingivalis
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
1

Lysine-specific gingipain K and heme-hemoglobin receptor HmuR are involved in heme utilization in Porphyromonas gingivalis

100%
Simpson W., Olczak T., Genco C. A.
Acta Biochimica Polonica
|
2004
|
tom 51
|
nr 1
We have previously reported on the identification and characterization of the Porphyromonas gingivalis A7436 strain outer membrane receptor HmuR, which is involved in the acquisition of hemin and hemoglobin. We demonstrated that HmuR interacts with the lysine- (Kgp) and arginine- (HRgpA) specific proteases (gingipains) and that Kgp and HRgpA can bind and degrade hemoglobin. Here, we report on the physiological significance of the HmuR-Kgp complex in heme utilization in P. gingivalis through the construction and characterization of a defined kgp mutant and a hmuR kgp double mutant in P. gingivalis A7436. The P. gingivalis kgp mutant ex­hibited a decreased ability to bind both hemin and hemoglobin. Growth of this strain with hemoglobin was delayed and its ability to utilize hemin as a sole iron source was diminished as compared to the wild type strain. Inactivation of both the hmuR and kgp genes resulted in further decreased ability of P. gingivalis to bind hemoglobin and hemin, as well as diminished ability to utilize either hemin or hemoglobin as a sole iron source. Collectively, these in vivo results further confirmed that both HmuR and Kgp are involved in the utilization of hemin and hemoglobin in P. gingivalis A7436.
2
Content available remote

Platelet-activating factor mediates Porphyromonas gingivalis lipopolysaccharide interference with salivary mucin synthesis via phosphatidylinositol 3-kinase-dependent constitutive nitric-oxide synthase activation

100%
Slomiany B. L., Slomiany A.
Journal of Physiology and Pharmacology
|
2004
|
tom 55
|
nr 1,1
Platelet -activating factor (PAF), a phospholipid-derived messenger molecule, is now recognized as the most proximal mediator of cellular events triggered by bacterial lipopolysaccharide (LPS) stimulation. In this study, we assessed the role of PAF in the disturbances in salivary mucin synthesis evoked by LPS of periodontopathic bacterium, P. gingivalis. Using primary culture of mucous acinar cells of sublingual salivary gland, we show that a specific PAF antagonist, BN52020, prevents in a dose-dependent fashion (up to 83.7%) the LPS-induced reduction in mucin synthesis, and the effect is reflected in a marked decrease in the LPS-induced apoptosis (74.8%), NO generation (82.6%), and the expression of TNF-alpha (76.1%). The impedance by BN52020 of the LPS inhibitory effect on mucin synthesis was blocked by wortmannin, an inhibitor of phosphatidylinositol 3-kinase (PI3K), which also obviated the inhibitory effect of BN52020 on the LPS-induced upregulation in apoptosis, TNF-alpha , and NO. A potentiation in the impedance by BN52020 of the LPS detrimental effect on mucin synthesis was however attained with NOS-2 inhibitor, 1400W, while cNOS inhibitor, L-NNA caused a reduction in the impedance effect of BN52020. However, while 1400W and BN52020 countered the potentiating effect of wortmannin on the LPS-induced decrease in mucin synthesis, a further exacerbation of the effect of wortmannin occurred in the presence of L-NNA. The findings implicate PAF as a pivotal factor affecting the extent of pathological consequences of P. gingivalis infection on salivary glands capacity for mucin production, and suggest that its release in response to the LPS serves as a negative regulator of PI3K controlling the pathway of cNOS activation.
3
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Antimicrobial effects of Citrus sinensis peel extracts against periodontopathic bacteria: an in vitro study

84%
Hussain K. A., Tarakji B., Kandy B. P. P., John J., Mathews J., Ramphul V., Divakar D. D.
Roczniki Państwowego Zakładu Higieny
|
2015
|
tom 66
|
nr 2
Background. Use of plant extracts and phytochemicals with known antimicrobial properties may have great significance in therapeutic treatments. Objective. To assess the in vitro antimicrobial potential and also determine the minimum inhibitory concentration (MIC) of Citrus sinensis peel extracts with a view of searching a novel extract as a remedy for periodontal pathogens. Materials and Methods. Aqueous and ethanol (cold and hot) extracts prepared from peel of Citrus sinensis were screened for in vitro antimicrobial activity against Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia, using agar well diffusion method. The lowest concentration of every extract considered as the minimal inhibitory concentration (MIC) values were determined for both test organisms. Confidence level and level of significance were set at 95% and 5% respectively. Results. Prevotella intermedia and Porphyromonas gingivalis were resistant to aqueous extracts while Aggregatibacter actinomycetemcomitans was inhibited at very high cncentrations. Hot ethanolic extracts showed significantly higher zone of inhibition than cold ethanolic extract. Minimum inhibitory concentration of hot and cold ethanolic extracts of Citrus sinensis peel ranged between 12-15 mg/ml against all three periodontal pathogens. Conclusions. Both extracts were found sensitive and contain compounds with therapeutic potential. Nevertheless, clinical trials on the effect of these plants are essential before advocating large-scale therapy.
4

Oddzialywania komorek w substancji miedzykomorkowej

84%
Porwit-Bobr Z.
Postępy Biologii Komórki. Suplement
|
1995
|
nr 05
35-40
5

Influence of Lactobacillus rhamnosus GG metabolites on growth of periodontal diseases bacteria

84%
Balejko E., Kucharska E., Balejko J.
Electronic Journal of Polish Agricultural Universities. Series: Biotechnology
|
2012
|
tom 15
|
nr 2
6

Porphyromonas gingivalis proteinases in periodontitis, a review

84%
Potempa J., Travis J.
Acta Biochimica Polonica
|
1996
|
tom 43
|
nr 3
Porphyromonas gingivalis has been closely associated with the initiation and progression of some forms of periodontal diseases and its proteolytic enzymes have been implicated in invasion, tissue destruction and evasion of host antibacterial defenses. Recently, the primary focus of research has been on cysteine proteinases, referred to as gingipain R and gingipain K which are produced in large quantities and are directly involved in pathological events during development and progression of periodontitis, contributing to clinical hallmarks of the disease including: flow of gingival crevicular fluid, neutrophil accumulation and bleeding on probing. Gingi­pain R exists as 110-, 95-, 70- to 90- and 50-kDa proteins, the first two being a complex of the 50-kDa catalytic subunit with hemagglutinin/adhesins, with or without an added membrane anchorage peptide. The other forms are single-chain enzymes. The predominant form of gingipain K in P. gingivalis strains is a complex of a 60-kDa catalytic protein with hemagglutinin/adhesins. Molecular cloning and structural characterization of the gingipain R and gingipain K genes has shown that they code for 1704 and 1722 amino-acid residue preproenzymes, respectively. Although both structures show no similarity within the preprofragment and only limited identity within the catalytic domain (27%) they are essentially identical within the putative hemagglutinin/adhesin domain. Furthermore, on the basis of gene structure it is now apparent that various soluble and membrane bound forms of gingipains are derived through proteolytic processing of the preproenzymes, and it can be assumed that the Arg-X-specific enzyme is responsible for this processing.
7

Inhibitors of benzamidine type influence the virulence properties of Porphyromonas gingivalis strains

84%
Eick S., Pfister W., Sturzebecher U., Jarema S., Sturzebecher J.
Acta Biochimica Polonica
|
2003
|
tom 50
|
nr 3
Synthetic inhibitors of benzamidine type have been found to have inhibiting effects on arginine specific cysteine proteinases of P. gingivalis. The purpose of our study was to assess the effects of these inhibitors on the virulence properties of two P. gingivalis strains, the reference strain ATCC 33277 and JH16-1, a clinical isolate ob­tained from a patient with severe periodontitis. The inhibitors tested were pentami- dine, benzamidine, three bis-benzamidine derivatives with a pentamidine-related structure, one bis-benzamidine derivative with another structure, and one arginine derivative as a negative control, each in the concentrations of 2 uM and 20 uM. As vir­ulence criteria the following parameters were determined: arginine-specific amidolytic activity, growth inhibition, hemagglutination of sheep erythrocytes, adher­ence to KB cells and immuno-phagocytosis including intracellular killing. Pentami- dine and the bis-benzamidine derivatives with pentamidine-related structure showed the most remarkable effects on reduction of amidolytic activity by 35%, growth inhibi­tion and reduced hemagglutination. Except for the arginine derivative all other inhibi­tors tested enhanced the phagocytosis capacities of granulocytes. No clear influence of the inhibitors on adherence of P. gingivalis to KB cells was seen. Although in vitro effects of the synthetic inhibitors of cysteine proteinases on virulence of P. gingivalis were observed further in vitro tests concerning immunomodulatory effects should be done before these substances are used for therapy in clinically controlled studies.
8
Content available remote

Activation of peroxisome proliferator-activated receptor gamma impedes Porphyromonas gingivalis lipopolysaccharide interference with salivary mucin synthesis through phosphatidylinositol 3-kinase - ERK pathway

84%
Slomiany B. L., Slomiany A.
Journal of Physiology and Pharmacology
|
2003
|
tom 54
|
nr 1
Peroxisome proliferator-activated receptor (PPAR), a member of the superfamily of nuclear receptor transcription factors, plays a critical role in the regulation of the expression of genes associated with inflammation. Using mucous acinar cells of sublingual salivary gland, we investigated the effect of PPAR activation on the disturbances in salivary mucin synthesis evoked by lipopolysaccharide (LPS) of periodontopathic bacterium, P. gingivalis. Exposure of the acinar cells to the LPS led to a dose-dependent decrease (up to 58.4%) in mucin synthesis, accompanied by a massive enhancement in apoptosis and NO production, and an induction in inducible nitric oxide synthase (NOS-2) activity. Activation of PPAR with a specific synthetic agonist, ciglitazone, prevented in a dose-dependent fashion the LPS-induced reduction in mucin synthesis, and the effect was reflected in a marked decrease in apoptosis, NO generation, and the expression of NOS-2 activity. The impedance by ciglitazone of the LPS-induced changes in mucin synthesis was blocked by PD98059, an inhibitor of extracellular signal regulated kinase (ERK), as well as wortmannin, an inhibitor of phosphatidylinositol 3-kinase (PI3K). Moreover, both agents caused further enhancement in the LPS-induced nitric oxide generation and countered the inhibitory effect of ciglitazone on the LPS-induced upregulation in NOS-2. The findings suggest that the impedance of P. gingivalis LPS inhibition of salivary mucin synthesis by PPAR agonist, ciglitazone, involves activation of ERK pathway by PI3K.
9

In vitro invasion and survival of Porphyromonas gingivalis in gingival fibroblasts; role of the capsule

67%
Irshad M., Van der Reijden W. A., Crielaard W., Laine M. L.
Archivum Immunologiae et Therapiae Experimentalis
|
2012
|
tom 60
|
nr 6
10
Content available remote

Protective effect of oral Lactobacilli in pathogenesis of chronic periodontitis

67%
Szkaradkiewicz A. K., Karpinski T. M., Zeidler A., Wyganowska-Swiatkowska M., Szkaradkiewicz A.
Journal of Physiology and Pharmacology
|
2011
|
tom 62
|
nr 6
11

Microbiology of chronic periodontitis

67%
Szkaradkiewicz A. K., Karpinski T. M.
Journal of Biology and Earth Sciences
|
2013
|
tom 03
|
nr 1
12

Roznorodne funkcje wybranych pigmentow bakteryjnych

59%
Wolska K. I., Grudniak A. M., Kraczkiewicz-Dowjat A., Kurek A.
Postępy Mikrobiologii
|
2010
|
tom 49
|
nr 2
105-114
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.