Aptamer Based SPREETA Sensor for the Detection of Porphyromonas gingivalis G-Protein

We have developed an aptamer that specifically binds to Porphyromonas gingivalis to reduce the cellular damage caused by P. gingivalis infection and applied it as a biosensor. P. gingivalis is one of the major pathogens causing destructive periodontal disease among the periodontal microorganisms constituting complex biofilms. Porphyromonas gingivalis G-protein (PGP) known to play an important role in the transmission of germs was used as a target protein for the screening of aptamer. The aptamer that has binds to the G-protein of P. gingivalis, was screened and developed through the Systemic Evolution of Ligands by Exponential Energy (SELEX) method. Modified-Western blot analysis was performed with the aptamer which consisted of 38 single-stranded DNA to confirm the selectivity. ELONA (enzyme linked oligonucleotide assay) used to confirm that the aptamer was sensitive to PGP even at low concentration of 1 μg/ml. For the rapid detection of P. gingivalis, we constructed a surface plasmon resonance biosensor with SPREETA using the PGP aptamer. It was confirmed that PGP could be detected as low concentration as at 0.1 pM, which is the minimum concentration of aptamer sensor within 5 min. Based on these results, we have constructed a SPREETA biosensor based on aptamer that can bind to P. gingivalis G-protein. It can be used as an infection diagnosis system to rapidly diagnose and analyze oral diseases caused by P. gingivalis.

Antioxidant and Anti-Inflammatory Activities of Lindera glauca Extracts

INTRODUCTION

The current study investigated the antioxidant and anti-inflammatory effects of ethanol extracts from Lindera glauca twig (LGT) and leaf/stem (LGLS).

METHODS

The antioxidant activities were measured by total content of polyphenol and flavonoid, DPPH radical scavenging, and ABTS+ radical scavenging activity. To evaluate the anti-inflammatory effect in the LPS-induced RAW 264.7 cells, protein and mRNA expression of major inflammatory factors were analyzed using Western blot analysis and RT-PCR.

RESULTS

The total polyphenol content of LGT and LGLS was 88.45 ± 11.74 and 115.75 ± 7.87 GA mg/g, respectively. The total flavonoid content was 66 ± 2.89 and 74.33 ± 2.89 QE mg/g. Both LGT and LGLS showed high DPPH and ABTS+ radical scavenging activities. Neither LGT nor LGLS was cytotoxic to RAW 264.7 cells. The anti-inflammatory activities were measured by LPS-induced RAW 264.7 cells. LGT and LGLS showed inhibition of the LPS-induced production of nitric oxide (NO), inducible NO synthase, cyclooxygenase-2 at the protein and mRNA levels, as determined by Western blotting and RT-PCR, respectively. In addition, the release of tumor necrosis factor-α and interleukin-6 mRNA expression levels of these cytokines was reduced by LGT and LGLS.

CONCLUSION

These results suggest that LGT and LGLS extracts have potential for use as a functional antioxidant and anti-inflammatory ingredient in cosmetic industry.

Anticancer Activity of Astaxanthin-Incorporated Chitosan Nanoparticles

Astaxanthin (AST)-encapsulated nanoparticles were fabricated using glycol chitosan (Chito) through electrostatic interaction (abbreviated as ChitoAST) to solve the aqueous solubility of astaxanthin and improve its biological activity. AST was dissolved in organic solvents and then mixed with chitosan solution, followed by a dialysis procedure. All formulations of ChitoAST nanoparticles showed small diameters (less than 400 nm) with monomodal distributions. Analysis with Fourier transform infrared (FT-IR) spectroscopy confirmed the specific peaks of AST and Chito. Furthermore, ChitoAST nanoparticles were formed through electrostatic interactions between Chito and AST. In addition, ChitoAST nanoparticles showed superior antioxidant activity, as good as AST itself; the half maximal radical scavenging concentrations (RC50) of AST and ChitoAST nanoparticles were 11.8 and 29.3 µg/mL, respectively. In vitro, AST and ChitoAST nanoparticles at 10 and 20 µg/mL properly inhibited the production of intracellular reactive oxygen species (ROSs), nitric oxide (NO), and inducible nitric oxide synthase (iNOS). ChitoAST nanoparticles had no significant cytotoxicity against RAW264.7 cells or B16F10 melanoma cells, whereas AST and ChitoAST nanoparticles inhibited the growth of cancer cells. Furthermore, AST itself and ChitoAST nanoparticles (20 µg/mL) efficiently inhibited the migration of cancer cells in a wound healing assay. An in vivo study using mice and a pulmonary metastasis model showed that ChitoAST nanoparticles were efficiently delivered to a lung with B16F10 cell metastasis; i.e., fluorescence intensity in the lung was significantly higher than in other organs. We suggest that ChitoAST nanoparticles are promising candidates for antioxidative and anticancer therapies of B16F10 cells.

Screening and development of DNA aptamers specific to several oral pathogens

Aptamers are composed of single-stranded oilgonucleotides that can selectively bind desired molecules. It has been reported that RNA or DNA could act as not only a genetic messenger but also a catalyst in metabolic pathways. RNA aptamers (average sizes 40-50 bp) are smaller than antibodies and have strong binding capacities to target molecules, similar to antigen-antibody interactions. Once an aptamer was selected, it can be readily produced in large quantities at low cost. The objectives of this study are to screen and develop aptamers specific to oral pathogens such as Porphyromonas gingivalis, Treponema denticola, and Streptococcus mutans. The bacterial cell pellet was fixed with formaldehyde as a target molecule for the screening of aptamers. The SELEX method was used for the screening of aptamers and a modified western blot analysis was used to verify their specificities. Through SELEX, 40 kinds of aptamers were selected and the specificity of the aptamers to the bacterial cells was confirmed by modified western blot analysis. Through the SELEX method, 40 aptamers that specifically bind to oral pathogens were screened and isolated. The aptamers showed possibility as effective candidates for the detection agents of oral infections.

Multiplex fiber optic biosensor for detection of Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella enterica from ready-to-eat meat samples

Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella enterica are the most common foodborne bacterial pathogens and are responsible for many outbreaks. Therefore, multiplex detection of these three using a single assay platform is highly desirable. The objective was to develop and optimize a fiber optic sensor for simultaneous detection of these three from food. The streptavidin coated optical waveguides were immobilized with biotinylated polyclonal antibodies and exposed to the bacterial suspensions or enriched food samples for 2 h. Pathogens were detected after reacting with Alexa-Fluor 647-labeled monoclonal antibodies. Ready-to-eat beef, chicken and turkey meats were inoculated with each pathogen (~100 cfu/25 g), enriched in SEL (Salmonella, E. coli, Listeria), a multipathogen selective enrichment broth for 18 h and tested with the biosensor. The biosensor was able to detect each pathogen, individually or in a mixture with very little cross-reactivity. The limit of detection for the sensor was ~10(3) cfu/ml for all three pathogens. Furthermore, the biosensor successfully detected each pathogen, grown in a mixture from enriched meat samples under 24 h. The pathogen presence was further verified by PCR and immunofluorescence assay. The multiplex fiber optic sensor shows promise for detection of the three pathogens if present in the same sample eliminating the use of multiple single pathogen detection platforms.

Antibody-aptamer functionalized fibre-optic biosensor for specific detection of Listeria monocytogenes from food

AIM

To develop antibody-aptamer functionalized fibre-optic biosensor for specific detection of Listeria monocytogenes from food products.

METHODS AND RESULTS

Aptamer, a single-stranded oligonucleotide ligand that displays affinity for the target molecule, was used in the assay to provide sensor specificity. Aptamer-A8, specific for internalin A, an invasive protein of L. monocytogenes, was used in the fibre-optic sensor together with antibody in a sandwich format for detection of L. monocytogenes from food. Biotinylated polyclonal anti-Listeria antibody, P66, was immobilized on streptavidin-coated optical waveguide surface for capturing bacteria, and Alexa Fluor 647-conjugated A8 was used as a reporter. The biosensor was able to selectively detect pathogenic Listeria in pure culture and in mixture with other bacteria at a concentration of approx. 10(3) CFU ml(-1). This sensor also successfully detected L. monocytogenes cells from artificially contaminated (initial inoculation of 10(2) CFU 25 g(-1) ) ready-to-eat meat products such as sliced beef, chicken and turkey after 18 h of enrichment.

CONCLUSION

Based on the data presented in this study, the antibody-aptamer functionalized fibre-optic biosensor could be used as a detection tool for sensitive and specific detection of L. monocytogenes from foods.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study demonstrates feasibility and novel application of aptamer on fibre-optic biosensor platform for the sensitive detection of L. monocytogenes from food products.

Hyperosmotic Stimulus Down-regulates 1alpha, 25-dihydroxyvitamin D(3)-induced Osteoclastogenesis by Suppressing the RANKL Expression in a Co-culture System

The hyperosmotic stimulus is regarded as a mechanical factor for bone remodeling. However, whether the hyperosmotic stimulus affects 1alpha, 25-dihydroxyvitamin D(3) (1alpha,25(OH)(2)D(3))-induced osteoclastogenesis is not clear. In the present study, the effect of the hyperosmotic stimulus on 1alpha,25(OH)(2)D(3)-induced osteoclastogenesis was investigated in an osteoblast-preosteoclast co-culture system. Serial doses of sucrose were applied as a mechanical force. These hyperosmotic stimuli significantly evoked a reduced number of 1alpha,25(OH)(2)D(3)-induced tartrate-resistant acid phosphatase-positive multinucleated cells and 1alpha,25(OH)(2)D(3)-induced bone-resorbing pit area in a co-culture system. In osteoblastic cells, receptor activator of nuclear factor kappaB ligand (RANKL) and Runx2 expressions were down-regulated in response to 1alpha,25(OH)(2)D(3). Knockdown of Runx2 inhibited 1alpha,25(OH)(2)D(3)-induced RANKL expression in osteoblastic cells. Finally, the hyperosmotic stimulus induced the overexpression of TonEBP in osteoblastic cells. These results suggest that hyperosmolarity leads to the down-regulation of 1alpha,25(OH)(2)D(3)-induced osteoclastogenesis, suppressing Runx2 and RANKL expression due to the TonEBP overexpression in osteoblastic cells.

Synthesis of carbon containing TiO2 nano powders by aerosol flame deposition for photocatalyst

In-situ carbon-doped-TiO2 nano-powder was prepared by an AFD (aerosol flame deposition) technique using ethanol and isopropanol, and the photocatalytic activity of the prepared powder was examined. There were no significant effect of the solvents on the phase of the prepared TiO2, but the level of carbon in the deposits prepared with ethanol was lower than that prepared with isopropanol. Also, the average sizes of the particles prepared with ethanol were slightly smaller than that formed with isopropanol. All the samples showed excellent photocatalytic activity in the decomposing of methylene blue (MB). We even observed photocatalytic activity of the powder under visible light irradiation, although the decomposition rate of MB under this irradiation was slightly slower than under UV-A light irradiation.

Surface modification of orthodontic wires with photocatalytic titanium oxide for its antiadherent and antibacterial properties

OBJECTIVE

To test the antiadherent and antibacterial properties of surface modification of orthodontic wires with photocatalytic titanium oxide (TiO(2)).

MATERIALS AND METHODS

TiO(2) was coated on the surface of the orthodontic wires by a sol-gel thin film dip-coating method. Bacterial adhesion to the wires was evaluated by the weight change of the wires. The antibacterial activity of the surface-modified orthodontic wires was demonstrated by the dilution agar plate method for Streptococcus mutans and spectrophotometry for Porphyromonas gingivalis.

RESULTS

The orthodontic wires coated with the photocatalytic TiO(2) showed an antiadherent effect against S. mutans compared with the uncoated wires. The bacterial mass that bound to the TiO(2)-coated orthodontic wires remained unchanged, whereas that of the uncoated wires increased by 4.97%. Furthermore, the TiO(2)-coated orthodontic wires had a bactericidal effect on S. mutans and P. gingivalis, which cause dental caries and periodontitis, respectively. The antiadherent and antibacterial mechanisms of TiO(2) to break down the cell wall of those bacteria were revealed by scanning electron microscopy.

CONCLUSION

The surface modification of orthodontic wires with photocatalytic TiO(2) can be used to prevent the development of dental plaque during orthodontic treatment.

Formation of spacing pattern and morphogenesis of chick feather buds is regulated by cytoskeletal structures

Chick feather buds develop sequentially in a hexagonal array. Each feather bud develops with anterior posterior polarity, which is thought to develop in response to signals derived from specialized regions of mesenchymal condensation and epithelial thickening. These developmental processes are performed by cellular mechanisms, such as cell proliferation and migration, which occur during chick feather bud development. In order to understand the mechanisms regulating the formation of mesenchymal condensation and their role in feather bud development, we explanted chick dorsal skin at stage HH29+ with cytochalasin D, which inhibits cytoskeletal formation. We show that the aggregation of mesenchymal cells can be prevented by cytochalasin D treatment in a concentration-dependent manner. Subsequently, cytochalasin D disrupts the spacing pattern and inhibits feather bud axis formation as well. In addition, expression patterns of Bmp-4 and Msx-2, key molecules for early feather bud development, were disturbed by cytochalasin D treatment. Our results fully indicate that both the cytoskeletal structure and cell activity via gene regulation are of fundamental importance in mesenchymal condensation leading to proper morphogenesis of feather bud and spacing pattern formation.

Bumetanide, the specific inhibitor of Na+-K+-2Cl- cotransport, inhibits 1alpha,25-dihydroxyvitamin D3-induced osteoclastogenesis in a mouse co-culture system

The Na(+)-K(+)-2Cl(-) cotransporter (NKCC1) is responsible for ion transport across the secretory and absorptive epithelia, the regulation of cell volume, and possibly the modulation of cell growth and development. It has been reported that a variety of cells, including osteoblasts, contain this cotransporter. In this study, the physiological role of NKCC1 in osteoclastogenesis was exploited in a co-culture system. Bumetanide, a specific inhibitor of NKCC1, reduced the number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells. In order to investigate the mechanism by which bumetanide inhibits osteoclastogenesis, the mRNA expressions of the receptor activator of nuclear factor (NF)-kappaB ligand (RANKL) and osteoprotegerin (OPG) were analysed by RT-PCR. Exposure of osteoblastic cells to a medium containing 1 micro M bumetanide reduced RANKL mRNA expression induced by 10 nM 1alpha,25-dihydroxyvitamin D3 (1alpha,25(OH)2D3, in a dose-dependent manner. In addition, RANKL expression was also analysed with enzyme-linked immunosorbant assay (ELISA) using anti-RANKL antibody. The expression of RANKL was decreased with the increase of bumetanide concentration. In contrast, the expression of OPG mRNA, a novel tumour necrosis factor (TNF) receptor family member was increased in the presence of bumetanide. These results imply that bumetanide inhibits osteoclast differentiation by reducing the RANKL/OPG ratio in osteoblastic cells. However, no significant difference in M-CSF mRNA expression was observed when bumetanide was added. Also, we found that the phosphorylation of c-Jun NH2-terminal kinase (JNK), which regulates the activity of various transcriptional factors, was reduced by bumetanide treatment. Conclusively, these findings suggest that NKCC1 in osteoblasts has a pivotal role in 1alpha,25(OH)2D3-induced osteoclastogenesis partly via the phosphorylation of JNK.

Effects of whole cell sonicates of Treponema lecithinolyticum on osteoclast differentiation

BACKGROUND

Alveolar bone destruction is a characteristic feature of periodontal diseases and multinucleated osteoclast cells derived from hemopoietic cells are responsible for bone resorption. Treponema lecithinolyticum is a novel oral spirochete isolated from the periodontal lesions.

METHODS

The effect of whole cell sonicates on the osteoclast differentiation was examined in a co-culture system of hemopoietic mouse bone marrow cells and calvaria derived-osteoblastic cells to clarify the role of T. lecithinolyticum in the alveolar bone destruction associated with periodontal diseases. The differentiated osteoclasts were confirmed by tartrate-resistant acid phosphatase (TRAP) staining.

RESULTS

Sonicates of this bacterium stimulated the osteoclast formation in the co-culture system in a dose-dependent manner. The sonicates-induced osteoclast formation was partially inhibited by the heat treatment of sonicates. Indomethacin, which is a prostaglandin inhibitor, decreased the osteoclast formation induced by the bacterial sonicates.

CONCLUSIONS

These findings suggest that T. lecithinolyticum induces osteoclast differentiation by a prostaglandin E2-dependent mechanism and that heat-labile components may be involved in this process.

A novel antibacterial agent derived from the C-terminal domain of streptococcus mutans GTP-binding protein

A decapeptide, P1, homologous to part of the Streptococcus mutans G-protein (SGP) and the Escherichia coli Era protein, was synthesized and examined for growth-inhibitory effects. When P1 10 mg/L was added to E. coli DH5, the viability of the cells was reduced by 13%. Addition of lauric acid enhanced the bactericidal effects of P1 (68% killing in the presence of P1 plus lauric acid). Similar enhancements were observed for mono lauroyl-rac-glycerol (MLG) and sodium dodecyl sulphate (SDS). In cultures treated with both P1 and MLG, there were more elongated cells than in cultures treated with detergent or peptide alone. As with E. coli, the bactericidal effects of P1 on S. mutans were significantly enhanced in the presence of the detergent lauric acid. The combination of the two effectors produced >90% killing of S. mutans. Likewise, the combined action of P1 plus lauric acid reduced the viability of Listeria monocytogenes. P1 did not appear to be toxic to human gingival epithelial cells when added at concentrations < or = 1000 mg/L. Therefore, P1 has properties which could allow it to be used as an antibacterial agent.

Protein interactions of SGP, an essential Streptococcus mutans GTPase, revealed by biochemical and yeast two-hybrid system analyses

SGP, a Streptococcus mutans essential GTPase, plays a role in the stress response of the organism. Recently, we proposed that one of the physiological functions of the SGP is the modulation of the GTP/GDP ratio under different growth conditions. In order to further determine the functions of SGP and its possible interactions with other molecules, we carried out immunoprecipitation, SGP binding, and the yeast two-hybrid system analyses. These approaches suggest that SGP may oligomerize and such interactions could be important for the function of this regulatory protein.

Purification and properties of bacteriolytic enzymes from Bacillus licheniformis YS-1005 against Streptococcus mutans

To find a novel lytic enzyme against cariogenic Streptococci, strains showing strong lytic activity have been screened from soil using Streptococcus mutans. A strain identified as Bacillus licheniformis secreted two kinds of lytic enzymes, which were purified by methanol precipitation, CM-cellulose chromatography, gel filtration, and hydroxyapatite chromatography. The molecular weights of these two enzymes, L27 and L45, were 27,000 and 45,000, respectively. Optimum pH and temperature of both enzymes for lytic activity were pH 8 and 37 degrees C. L27 and L45 digest the peptide linkage between L-Ala and D-Glu in peptidoglycan of Streptococcus mutans. The lytic activity was highly specific for Streptococcus mutans, suggesting their potential use as a dental care product.