Cyclodextrin-Assisted Surface-Enhanced Photochromic Phenomena of Tungsten(VI) Oxide Nanoparticles for Label-Free Colorimetric Detection of Phenylalanine.

Herein are presented the results of experiments designed to evaluate the effectiveness of host-guest interactions in improving the sensitivity of colorimetric detection based on surface-enhanced photochromic phenomena of tungsten(VI) oxide (WO) nanocolloid particles. The UV-induced photochromic coloration of WO nanocolloid particles in the presence of aromatic α-amino acid (AA), l-phenylalanine (Phe) or l-2-phenylglycine (Phg), and heptakis(2,3,6-tri--methyl)-β-cyclodextrin (TMβCDx) in an aqueous system was investigated using UV-vis absorption spectrometry. The characteristics of the adsorption modes and configurations of AAs on the WO surface have also been identified by using a combination of adsorption isotherm analysis and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR).

Inhibition of biofilm formation, quorum sensing and other virulence factors in by polyphenols of leaves.

Quorum sensing (QS) enables virulence factors in bacteria for biofilm formation and pathogenic invasion. Therefore, quorum quenching (QQ), disruption of QS circuit, becomes an alternative antimicrobial therapy. In this study, leaf extract of (GP) was used to inhibit biofilm and virulent factors in .

Computational prediction of active sites and ligands in different AHL quorum quenching lactonases and acylases.

With the emergence of multidrug-resistant 'superbug', conventional treatments become obsolete. Quorum quenching (QQ), enzyme-dependent alteration of quorum sensing (QS), is now considered as a promising antimicrobial therapy because of its potentiality to impede virulence gene expression without resulting in growth inhibition and antibiotic resistance. In our study, we intended to compare between two major QQ enzyme groups (i.

Purification and characterization of hemolysin from periodontopathogenic bacterium Eikenella corrodens strain 1073.

Eikenella corrodens 1073 was found to show hemolytic activity when grown on sheep blood agar. A high and dose-dependent hemolytic activity was detected in the cell envelope fraction, which was further purified by ion-exchange and gel-filtration chromatography. Consequently, a 65-kDa protein with hemolytic activity was obtained, suggesting that this protein might be a hemolysin.

Relationship between the risk for a shrimp allergy and freshness or cooking.

Tropomyosins are defined as risk factors for shrimp allergy. However, their concentration in different preparations has not been clarified. We quantified the tropomyosin concentration in shrimp meat, which was cooked using several methods or was stored under various conditions.

Unstable mutant lysozymes are degraded through the interaction with calnexin homolog Cne1p in Saccharomyces cerevisiae.

Cne1p is a yeast homolog of calnexin, which is a constituent of endoplasmic reticulum (ER)-associated protein quality control system in mammals. Cne1p may be involved in the degradation of misfolded lysozymes in Saccharomyces cerevisiae. To test this, c-Myc-tagged lysozymes were expressed in CNE1-deficient S.

Effects of the tea catechin epigallocatechin gallate on Porphyromonas gingivalis biofilms.

Aims: The aim of this study was to investigate the effects of tea catechin epigallocatechin gallate (EGCg) on established biofilms and biofilm formation by Porphyromonas gingivalis, a major pathogen of periodontal disease.

Methods And Results: Biofilm cell survival was measured using adenosine triphosphate (ATP) bioluminescence. In the presence of EGCg, the ATP level in cells of established biofilms was significantly decreased compared to the controls (P < 0·0001).

The periodontopathogenic bacterium Eikenella corrodens produces an autoinducer-2-inactivating enzyme.

Eikenella corrodens produces autoinducer-2 (AI-2) in the mid log phase, and AI-2 activity decreases dramatically during the stationary phase. We investigated the mechanism underlying this decrease in AI-2 activity. To analyze the mechanism, we extracted and purified AI-2 from the supernatant of mid-log-phase culture.

Contribution of structural reversibility to the heat stability of the tropomyosin shrimp allergen.

Tropomyosins are common heat-stable crustacean allergens. However, their heat stability and their effects on antigenicity have not been clarified. We purified tropomyosin in this study from raw kuruma prawns (Marsupenaeus japonicus) without heat processing.

LuxS affects biofilm maturation and detachment of the periodontopathogenic bacterium Eikenella corrodens.

Previously, we reported that biofilm formation of Eikenella corrodens is regulated by autoinducer-2 (AI-2), based on observations that biofilm-forming efficiency of ΔluxS mutant was greater than that of the wild type (Azakami et al., J. Biosci.

Synergistic effects of antibiotics and an N-acyl homoserine lactone analog on Porphyromonas gingivalis biofilms.

Aims: To investigate the effects of the combined application of an N-acyl homoserine lactone (HSL) analog and antibiotics on biofilms of Porphyromonas gingivalis, a major pathogen of periodontal disease.

Methods And Results: Antibiotics used were cefuroxime, ofloxacin and minocycline. A flow-cell model was used for biofilm formation.

Antibiofilm effects of azithromycin and erythromycin on Porphyromonas gingivalis.

Antibiotic resistance of biofilm-grown bacteria contributes to chronic infections, such as marginal and periapical periodontitis, which are strongly associated with Porphyromonas gingivalis. Concurrent azithromycin (AZM) administration and mechanical debridement improve the clinical parameters of periodontal tissue in situ. We examined the in vitro efficacy of AZM against P.

Genomic recombination through plasmid-encoded recombinase enhances hemolytic activity and adherence to epithelial cells in the periodontopathogenic bacterium Eikenella corrodens.

The periodontopathogenic bacterium Eikenella corrodens has an N-acetyl-D-galactosamine (GalNAc)-specific lectin, that contributes significantly to the pathogenicity of the bacterium. Recently, we reported that plasmid-mediated genomic recombination enhances the activity of this lectin. In this study, we investigated the effects of genomic recombination on certain virulence factors.

The inhibitory effects of catechins on biofilm formation by the periodontopathogenic bacterium, Eikenella corrodens.

Eikenella corrodens is a periodontopathogenic bacterium that forms biofilm even by itself. In this study, we investigated the inhibitory effects of catechins on E. corrodens biofilm formation.

Effects of various saccharides on the masking of epitope sites and uptake in the gut of cedar allergen Cry j 1-saccharide conjugates by a naturally occurring Maillard reaction.

A major allergen of Japanese cedar, Cry j 1, was conjugated with galactomannan (M(w) of 15 kDa), dextran (M(w) of 12 kDa), xyloglucan (M(w) of 1.4 kDa), and various monosaccharides through the Maillard reaction by dry-heating in 65% relative humidity. The Cry j 1-galactomannan conjugate completely masked the epitopes of the allergen in Cry j 1.

Reduction of antigenicity of Cry j 1, a major allergen of Japanese cedar pollen, by thermal denaturation.

The soluble aggregates of Cry j 1, a major allergen of Japanese cedar pollen, were formed without any coagulates during heat treatment at acidic pH 5, as shown in HPLC and SDS-PAGE patterns. A remarkable change in the CD spectrum was observed between native and heat-denatured Cry j 1 at a linear rate of 1 degrees C/min from 40 to 90 degrees C. The negative peak of native Cry j 1 at 222 nm was moved to 218 nm, suggesting the transition of an alpha-helix to beta-structure during heat denaturation.

Effects of Er:YAG laser irradiation on biofilm-forming bacteria associated with endodontic pathogens in vitro.

With the development of dental laser delivery systems that can enter into the root canals, it is possible to use Er:YAG lasers to remove the residual biofilm associated with infected root canals. We examined their effects against biofilms made of Actinomyces naeslundii, Enterococcus faecalis, Lactobacillus casei, Propionibacterium acnes, Fusobacterium nucleatum, Porphyromonas gingivalis, or Prevotella nigrescens in vitro. After Er:YAG laser irradiation with energy densities ranging between 0.

Amyloid fibril formation of hen lysozyme depends on the instability of the C-helix (88-99).

Stable and unstable mutant lysozymes in long helices B and C were constructed to evaluate the effect of the helices on amyloid fibril formation at pH 2. Stable mutant N27D and unstable mutant K33D in the B-helix did not change in amyloid fibril formation. In contrast, stable mutant N93D and unstable mutant K97D in the C-helix showed big differences in behavior as to amyloid fibril formation.

Relationship between the stability of hen egg-white lysozymes mutated at sites designed to interact with alpha-helix dipoles and their secretion amounts in yeast.

The positively charged lysine at the C-terminals of three long alpha-helices (5-15, 25-35, and 88-99) was replaced with alanine (K13A, K33A, K97A) or aspartic acid (K13D, K33D, K97D) in hen lysozyme by genetic engineering. The denaturation transition point (Tm) and Gibbs energy change Delta G of the mutant lysozymes decreased remarkably, suggesting that the positive charge at the C-terminals of helices is involved in the stabilization of the helix dipole. On the other hand, the non-charged asparagine at the N-terminal of the long alpha-helices (25-35 and 88-99) was replaced with negatively charged aspartic acid (N27D and N93D).

Soluble products from Eikenella corrodens induce cell proliferation and expression of interleukin-8 and adhesion molecules in endothelial cells via mitogen-activated protein kinase pathways.

The periodontal vasculature is profoundly affected during the progression of periodontitis, and several specific bacteria are believed to be involved in this inflammatory disease. Eikenella corrodens is one of the common bacteria detected in periodontitis diseased lesions; however, the function of this organism in periodontitis is not well understood. In this study, we investigated the E.

Characterization of autoinducer 2 signal in Eikenella corrodens and its role in biofilm formation.

Quorum sensing (QS) is a process by which bacteria communicate using secreted chemical signaling molecules called autoinducers (AIs). By this process, many bacterial species modulate the expression of a wide variety of physiological functions in response to changes in population density. In this study, the periodontal pathogen Eikenella corrodens was observed to secrete type 2 signaling molecules.

Plasmid-mediated genomic recombination at the pilin gene locus enhances the N-acetyl-D-galactosamine-specific haemagglutination activity and the growth rate of Eikenella corrodens.

Eikenella corrodens belongs to a group of periodontopathogenic bacteria and forms unique corroding colonies on solid medium due to twitching motility. It is believed that an N-acetyl-D-galactosamine (GalNAc)-specific lectin on the cell surface contributes significantly to its pathogenicity and can be estimated by its haemagglutination (HA) activity. Recently, a plasmid, pMU1, from strain 1073 has been found; this plasmid affects pilus formation and colony morphology.

Involvement of N-acetyl-D-galactosamine-specific lectin in biofilm formation by the periodontopathogenic bacterium, Eikenella corrodens.

Eikenella corrodens is known not only as one of the periodontopathogenic bacteria but also as a pathogen associated with many infectious diseases of humans. Dental plaque is a complex biofilm community comprised of many bacterial species. E.

Prevention of amyloid fibril formation of amyloidogenic chicken cystatin by site-specific glycosylation in yeast.

To address the role of glycosylation on fibrillogenicity of amyloidogenic chicken cystatin, the consensus sequence for N-linked glycosylation (Asn106-Ile108 --> Asn106-Thr108) was introduced by site-directed mutagenesis into the wild-type and amyloidogenic chicken cystatins to construct the glycosylated form of chicken cystatins. Both the glycosylated and unglycosylated forms of wild-type and amyloidogenic mutant I66Q cystatin were expressed and secreted in a culture medium of yeast Pichia pastoris transformants. Comparison of the amount of insoluble aggregate, the secondary structure, and fibrillogenicity has shown that the N-linked glycosylation could prevent amyloid fibril formation of amyloidogenic chicken cystatin secreted in yeast cells without affecting its inhibitory activities.

Isolation and characterization of a plasmid DNA from periodontopathogenic bacterium, Eikenella corrodens 1073, which affects pilus formation and colony morphology.

Eikenella corrodens (Ec) is one of a group of periodontopathogenic bacteria. A plasmid DNA (8.7 kb) isolated from Ec 1073 was designated pMU1.