Effect of Thai medicinal plant extracts on cell aggregation of Escherichia coli O157: H7.

Medicinal plants have been used for treating diarrhoea but the interference mechanisms are not clearly understood. One possible hypothesis is that of an effect on cell surface hydrophobicity of microbial cells. In this study, we examined cell aggregation affected by crude extracts of Thai medicinal plants on cell surface hydrophobicity of Escherichia coli strains by salt aggregation test. Correlation between minimal inhibitory concentration and cell aggregation was performed. Aqueous and ethanolic extracts of 8 medicinal plants including Acacia catechu, Holarrhena antidysenterica, Peltophorum pterocarpum, Piper sarmentosum, Psidium guajava, Punica granatum, Quercus infectoria, and Tamarindus indica were tested with E. coli O157: H7 and other E. coli strains isolated from human, porcine, and foods. Aqueous extracts of Peltophorum pterocarpum, Psidium guajava, and Punica granatum were highly effective against E. coli O157: H7 with the MIC values of 0.09 to 0.39, 0.19 to 0.78, and 0.09 to 1.56 mg/ml, respectively. Ethanolic extract of Quercus infectoria and Punica granatum demonstrated good MIC values of 0.09 to 0.78, and 0.19 to 0.78 mg/ml, respectively. It was established that aqueous extracts of Punica granatum and Piper sarmentosum at high concentration (25 mg/ml) enhanced cell aggregation of almost all E. coli strains while aqueous and ethanolic extracts ofQuercus infectoria enhanced cell aggregation of some E. coli strains. Correlation between minimal inhibitory concentration and cell aggregation was not found in this study

Raman Spectroscopy of DLC/a-Si Bilayer Film Prepared by Pulsed Filtered Cathodic Arc

DLC/a-Si bilayer film was deposited on germanium substrate. The a-Si layer, a seed layer, was firstly deposited on the substrate using DC magnetron sputtering and DLC layer was then deposited on the a-Si layer using pulsed filtered cathodic arc method. The bilayer films were deposited with different DLC/a-Si thickness ratios, including 2/2, 2/6, 4/4, 6/2, and 9/6. The effect of DLC/a-Si thickness ratios on the sp3 content of DLC was analyzed by Raman spectroscopy. The results show that a-Si layer has no effect on the structure of DLC film. Furthermore, the upper shift in G wavenumber and the decrease in ID/IG inform that sp3 content of the film is directly proportional to DLC thickness. The plot modified from the three-stage model informed that the structural characteristics of DLC/a-Si bilayer films are located close to the tetrahedral amorphous carbon. This information may be important for analyzing and developing bilayer protective films for future hard disk drive

Bactericidal, Bacteriolytic, and Antibacterial Virulence Activities of Boesenbergia pandurata (Roxb) Schltr Extract against Streptococcus pyogenes

Purpose: To determine the anti-Streptococcus pyogenes activity of the chloroform extract of Boesenbergia pandurata (Roxb.) Schltr. (Zingiberaceae) and investigate its possible antibacterial mechanisms of action.Methods: Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values were investigated against 47 clinical isolates of S. pyogenes. Time-kill study was performed to determine how quickly the extract acts on S. pyogenes. The ability of the extract to damage bacterial cell wall and effects on S. pyogenes virulence factors including protease enzyme and haemolysin were investigated.Results: The extract exhibited good antibacterial activity against all of the clinical isolates of S. pyogenes with similar MIC and MBC ranging from 3.91-62.50 μg/ml. Complete killing of the bacterial cells by the extract at concentrations of 4MIC, 2MIC, and MIC occurred within 4, 8, and 12 h, respectively. Treatment of the bacterial cells with the extract at 2MIC and 4MIC caused cell lysis. All the test concentrations (1/32 - 1/2MIC) produced no effects on protease and haemolysin enzymes.Conclusion: Boesenbergia pandurata extract has powerful in vitro activity against S. pyogenes. The ability of the extract to lyse the bacterial cells suggests that the mechanism of action may be associated with cell wall and cell membrane damage.Keywords: Antibacterial, Bacteriocidal, Bacteriolytic, Virulence, Boesenbergia pandurata, Streptococcus pyogenes

Anti-Streptococcus pyogenes Activity of Selected Medicinal Plant Extracts Used in Thai Traditional Medicine

Purpose: To evaluate the anti-Streptococcus pyogenes activity of selected medicinal plants used in Thai traditional medicine.Methods: Sixty-nine extracts of 51 selected Thai medicinal plant species were tested for anti-S. pyogenes activity by paper disc agar diffusion and broth microdilution methods.Results: Ten plants including Boesenbergia pandurata (Roxb.) Schltr., Cinnamomum bejolghota (Buch.-Ham.) Sweet, Cinnamomum porrectum (Roxb) Kosterm, Eleutherine americana Merr., Gymnopetalum cochinchinensis (Lour.) Kurz, Piper betle L., Quercus infectoria G. Olivier, Quisqualis indica L, Rhodomyrtus tomentosa (Aiton) Hassk., and Walsura robusta Roxb. demonstrated good antibacterial activity against S. pyogenes NPRC 101. These plants were selected and further evaluated for their anti-S. pyogenes activity against 11 isolates of S. pyogenes from patients with upper respiratory tract infections. Three plants including Boesenbergia pandurata, Eleutherine americana, and Rhodomyrtus tomentosa exhibited good antibacterial activity against all S. pyogenes isolates and produced similar activities against different tested isolates. Boesenbergia pandurata and Rhodomyrtus tomentosa demonstrated antibacterial activity with the same minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) range of 3.91 - 31.25 μg/ml whereas Eleutherine americana displayed MIC and MBC values of 250 and 250-500 μg/ml against all S. pyogenes isolates.Conclusion: Boesenbergia pandurata, Eleutherine americana, and Rhodomyrtus tomentosa have great antibacterial potentials against S. pyogenes.Keywords: Antibacterial activity, Boesenbergia pandurata, Eleutherine americana, Rhodomyrtus tomentosa, Streptococcus pyogenes, Thai medicinal plant, Upper respiratory tract infection

Enhanced stability of phenylethyl resorcinol in elastic vesicular formulations

Purpose: To enhance the stability and reduce photo-degradation of phenylethyl resorcinol (PR) by elastic vesicle formation.Methods: PR solution was stored at different temperatures, pH conditions, and under protected and unprotected natural light. The color of the solution and total active content were investigated. Three types of elastic vesicles, viz, ethosomes, transfersomes and invasomes, were prepared and their sedimentation in formulations and total active content were investigated before and after storage under various conditions for 4 months. The stability of the solutions and vesicular formulations were assessed.Results: PR solution was unstable at pH 9, higher temperature (70 ± 1 oC) and under natural light. The color of PR solution changed from colorless to orange tone and the PR content decreased. On the other hand, PR entrapped within ethosome, tranfersome and invasome vesicles showed better stability, color change was not observed in the formulations, and PR content remained > 90 %.Conclusion: All the vesicles display reduced degradation of PR under thermal and natural light. Thus, PR vesicular formulation enhances stability and improves the quality of the product for use in topical administration.Keywords: Phenylethyl resorcinol, Degradation, Ethosomes, Transfersomes, Invasomes, Topical administratio

Characterisation of C–F Polymer Film Formation on the Air-Bearing Surface Etched Sidewall of Fluorine-Based Plasma Interacting with AL 2

C–F polymer redeposition is generated on the etched sidewall of the patterned air-bearing surface (ABS). This C–F polymer is a by-product from fluorine-based plasma using a Surface Technology Systems multiplex-pro air-bearing etch (ABE). The morphology of the re-deposition and the composite element was observed by a scanning electron microscope (SEM). The chemical bonding results were characterised via X-ray photoelectron spectroscopy, attenuated total reflected infrared spectroscopy and visible Raman spectroscopy. The purpose of this work is to demonstrate a modification of AlF3 re-deposition to C–F polymer re-deposition, which is easily stripped out by an isopropyl alcohol-based solution. The benefit of this research is the removal of the re-deposition in the resist strip process without additional cleaning process steps

Synthesis of Antibodies-Conjugated Fluorescent Dye-Doped Silica Nanoparticles for a Rapid Single Step Detection of Campylobacter jejuni

The preparation of antibodies-conjugated fluorescent dye-doped silica nanoparticles (FDS-NPs) was developed to detect Campylobacter jejuni cells under a fluorescence microscope. The particles prepared by sol-gel microemulsion techniques have a round shape with an average size of 43 ± 4 nm. They were highly photo stable and could emit strong orange fluorescent for 60 min. Both amine- and carboxyl-functionalized properties were evident from FTIR and FT Raman spectra. The FDS-NPs conjugated with antibodies against C. jejuni were well dispersed in PBS solution at 20 mM of NaCl. The conjugation with monoclonal antibodies against C. jejuni was successful. The direct observation of the antibodies-conjugated FDS-NPs- that bounds C. jejuni with Petroff Hausser counting chamber at 40x was clear. The different focus lengths clearly separated bound and unbound FDS-NPs under the microscope. We successfully synthesis the bio-conjugated dye doped silica nanoparticles for C. jejuni that are easy to use and giving clear detection in due time

Apatite Formation on Rutile TiO2 Film Deposited Using Dual Cathode DC Unbalanced Magnetron Sputtering

Rutile TiO2 films were deposited on unheated stainless steel type 316L using dual cathode DC unbalanced magnetron sputtering. The effects of deposition time ranging 30, 60, 90, and 120 mins on the films structure were investigated. Moreover, all the samples were immersed in SBF for period times of 3 and 5 days also considered. The crystal structures were characterized by thin film X-ray diffraction (TF-XRD). The film’s thickness and surface morphology were evaluated using atomic force microscopy (AFM). The crystallinity, roughness, thickness, and grain size of rutile with only (110) plane increased with increased deposition time. After immersed samples in SBF for 3 day the highest and moderate crystallinity of apatite was observed on the 30 min and 90 min, respectively. However, the films deposited with 60 and 120 min cannot be observed the peak of apatite. An increase crystallinity of apatite clearly observed when after immersed in SBF for 5 day

Impact of Fusarium spp. infection of bread wheat (Triticum aestivum L.) on composition and quality of flour in association with EU maximum level for deoxynivalenol

Contamination of grain with mycotoxins such as deoxynivalenol (DON) is the major threat after Fusarium head blight (FHB) infection of wheat, however technological quality can also be impaired. The European Union has established maximum levels (ML) of DON for wheat grain and foodstuffs. The composition (starch, gluten proteins) and quality (protein content, sedimentation value, wet gluten, water absorption, mixing properties of dough, baking volume) of 72 flour Type 550 samples from two years either fulfilling or exceeding ML of 0.75 mg kg-1 were investigated. DO content of flours ranged widely from below limit of quantification to 11.84 mg kg-1. Aside from a slight loss of loaf shape in flours highly exceeding ML, no negative effect on composition and quality of flour was observed in flours exceeding ML compared to those fulfilling ML. A significant decrease in total glutenin and LMW-GS content did not correlate with any quality trait. Hence, if flours fulfill ML for DON, reduced technological quality due to FHB is not significant