scholarly journals Inactivation Efficacy of 405 nm LED Against Cronobacter sakazakii Biofilm

2020 ◽  
Vol 11 ◽  
Author(s):  
Yixiao Huang ◽  
Quanwei Pei ◽  
Ruisha Deng ◽  
Xiaoying Zheng ◽  
Jialu Guo ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Laser Scanning ◽  
Light Emitting Diode ◽  
Treated Group ◽  
Attenuated Total Reflection ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Pcr Analysis ◽  
Cronobacter Sakazakii ◽  
Sensitivity Change

The objectives of this study were to evaluate the inactivation efficacy of a 405-nm light-emitting diode (LED) against Cronobacter sakazakii biofilm formed on stainless steel and to determine the sensitivity change of illuminated biofilm to food industrial disinfectants. The results showed that LED illumination significantly reduced the population of viable biofilm cells, showing reduction of 2.0 log (25°C), 2.5 log (10°C), and 2.0 log (4°C) between the non-illuminated and LED-illuminated groups at 4 h. Images of confocal laser scanning microscopy and scanning electron microscopy revealed the architectural damage to the biofilm caused by LED illumination, which involved destruction of the stereoscopic conformation of the biofilm. Moreover, the loss of biofilm components (mainly polysaccharide and protein) was revealed by attenuated total reflection Fourier-transformed infrared spectroscopy, and the downregulation of genes involved in C. sakazakii biofilm formation was confirmed by real time quantitative PCR analysis, with greatest difference observed in fliD. In addition, the sensitivity of illuminated-biofilm cells to disinfectant treatment was found to significantly increased, showing the greatest sensitivity change with 1.5 log reduction between non-LED and LED treatment biofilms in the CHX-treated group. These results indicated that 405 nm LED illumination was effective at inactivating C. sakazakii biofilm adhering to stainless steel. Therefore, the present study suggests the potential of 405 nm LED technology in controlling C. sakazakii biofilms in food processing and storage, minimizing the risk of contamination.

scholarly journals Inhibition of Quorum Sensing and Biofilm Formation of Esculetin on Aeromonas Hydrophila

2021 ◽  
Vol 12 ◽  
Author(s):  
Bing Sun ◽  
Huaizhi Luo ◽  
Huan Jiang ◽  
Zhennan Wang ◽  
Aiqun Jia
Keyword(s):  
Quorum Sensing ◽  
Aeromonas Hydrophila ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Pcr Analysis ◽  
Swarming Motility ◽  
Gene Expression Levels ◽  
Good Agreement

Quorum sensing (QS) and biofilm formation inhibition activity of esculetin on Aeromonas hydrophila SHAe 115 were evaluated. Exposure to esculetin at 25, 50, and 100μg/ml significantly inhibited the production of protease and hemolysin, the formation of biofilms and attenuated the swarming motility of A. hydrophila SHAe 115. Biofilm forming inhibition was also observed through confocal laser scanning microscopy and scanning electron microscope. Quantitative real-time PCR analysis indicated that genes positively related to QS and biofilm formation were downregulated to varying degrees, while gene (litR) negatively related to biofilm formation was significantly upregulated. The phenotypic results were in good agreement with gene expression levels. These results indicated that esculetin would be a potential QS inhibitor for A. hydrophila.

scholarly journals Comparison of Antibacterial Adhesion When Salivary Pellicle Is Coated on Both Poly(2-hydroxyethyl-methacrylate)- and Polyethylene-glycol-methacrylate-grafted Poly(methyl methacrylate)

2018 ◽  
Vol 19 (9) ◽  
pp. 2764 ◽  
Author(s):  
Bor-Shiunn Lee ◽  
Yu-Jia Chen ◽  
Ta-Chin Wei ◽  
Tien-Li Ma ◽  
Che-Chen Chang
Keyword(s):  
Polyethylene Glycol ◽  
Bacterial Adhesion ◽  
Laser Scanning ◽  
Attenuated Total Reflection ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Hydroxyethyl Methacrylate ◽  
Surface Charges ◽  
Glycol Methacrylate ◽  
Salivary Pellicle

Although poly(2-hydroxyethyl methacrylate) (pHEMA) and polyethylene glycol methacrylate (PEGMA) have been demonstrated to inhibit bacterial adhesion, no study has compared antibacterial adhesion when salivary pellicle is coated on polymethyl methacrylate (PMMA) grafted with pHEMA and on PMMA grafted with PEGMA. In this study, PMMA discs were fabricated from a commercial orthodontic acrylic resin system (Ortho-Jet). Attenuated total reflection-Fourier transform infrared spectra taken before and after grafting confirmed that pHEMA and PEGMA were successfully grafted on PMMA. Contact angle measurements revealed PMMA-pHEMA to be the most hydrophilic, followed by PMMA-PEGMA, and then by PMMA. Zeta potential analysis revealed the most negative surface charges on PMMA-PEGMA, followed by PMMA-pHEMA, and then by PMMA. Confocal laser scanning microscopy showed green fluorescence in the background, indicating images that influenced the accuracy of the quantification of live bacteria. Both the optical density value measured at 600 nm and single plate-serial dilution spotting showed that pHEMA was more effective than PEGMA against Escherichia coli and Streptococcus mutans, although the difference was not significant. Therefore, the grafting of pHEMA and PEGMA separately on PMMA is effective against bacterial adhesion, even after the grafted PMMA were coated with salivary pellicle. Surface hydrophilicity, bactericidality, and Coulomb repulsion between the negatively charged bacteria and the grafted surface contributed to the effectiveness.

scholarly journals Inhibitive Properties of Benzyldimethyldodecylammonium Chloride on Microbial Corrosion of 304 Stainless Steel in a Desulfovibrio desulfuricans-Inoculated Medium

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 307 ◽  
Author(s):  
Chung-Wen Hsu ◽  
Tzu-En Chen ◽  
Kai-Yin Lo ◽  
Yueh-Lien Lee
Keyword(s):  
Stainless Steel ◽  
Laser Scanning ◽  
Steel Substrate ◽  
Desulfovibrio Desulfuricans ◽  
Corrosion Current ◽  
Laser Scanning Microscopy ◽  
304 Stainless Steel ◽  
Confocal Laser ◽  
Microbial Corrosion ◽  
Sulfate Reducing

Biocides are frequently used to control sulfate-reducing bacteria (SRB) in biofouling. The increasing restrictions of environmental regulations and growing safety concerns on the use of biocides result in efforts to minimize the amount of biocide use and develop environmentally friendly biocides. In this study, the antimicrobial activity and corrosion inhibition effect of a low-toxic alternative biocide, benzyldimethyldodecylammonium chloride (BDMDAC), on a 304 stainless steel substrate immersed in a Desulfovibrio desulfuricans (D. desulfuricans)-inoculated medium was examined. Potentiodynamic polarization curves were used to analyze corrosion behavior. Biofilm formation and corrosion products on the surfaces of 304 stainless steel coupons were examined using scanning electron microscopy (SEM), energy-dispersive X-ray spectrum, and confocal laser scanning microscopy (CLSM). Results demonstrated that this compound exhibited satisfactory results against microbial corrosion by D. desulfuricans. The corrosion current density and current densities in the anodic region were lower in the presence of BDMDAC in the D. desulfuricans-inoculated medium. SEM and CLSM analyses revealed that the presence of BDMDAC mitigated formation of biofilm by D. desulfuricans.

Culture and Detection of Campylobacter jejuni within Mixed Microbial Populations of Biofilms on Stainless Steel

2007 ◽  
Vol 70 (6) ◽  
pp. 1379-1385 ◽  
Author(s):  
SHERIASE Q. SANDERS ◽  
DOROTHY H. BOOTHE ◽  
JOSEPH F. FRANK ◽  
JUDY W. ARNOLD
Keyword(s):  
Stainless Steel ◽  
Campylobacter Jejuni ◽  
Laser Scanning ◽  
The United States ◽  
Laser Scanning Microscopy ◽  
Epifluorescence Microscopy ◽  
Confocal Laser ◽  
Atmospheric Conditions ◽  
Culture Methods ◽  
Bacterial Populations

Campylobacter jejuni is the most frequently reported cause of foodborne illness in the United States, but its survival outside the host is poor. The objective of this research was to examine the formation and composition of biofilms by C. jejuni alone and within mixed bacterial populations from the poultry-processing environment. C. jejuni growth was assessed with four media, two temperatures, and two atmospheric conditions to develop culture methods for liquid media that would allow growth within the biofilms. Growth kinetics was followed at four cell densities to determine temporal compatibility within biofilm mixtures. Analysis of the biofilms by confocal laser scanning microscopy showed that C. jejuni formed a biofilm when incubated without other bacteria. The average surface area of stainless steel covered by C. jejuni increased by 50% from 24 to 48 h, remained level to 96 h, and then decreased by 88% by 168 h. C. jejuni and mixed bacterial populations formed biofilms during incubation periods of up to 7 days. The area of the mixture was significantly greater than for C. jejuni alone at 24 h, was approximately the same at 48 h, and was significantly less by 168 h. When incubated with either of two initial inoculum densities of other bacteria, the number of C. jejuni was enhanced after 24 h. The intensity of fluorescence and cell viability were monitored by epifluorescence microscopy. This study provides the basis for studying interactions of Campylobacter spp. with other bacteria in the environment, which will aid in the design of effective intervention strategies.

scholarly journals Effect of Cinnamon Oil on icaA Expression and Biofilm Formation by Staphylococcus epidermidis

2009 ◽  
Vol 75 (21) ◽  
pp. 6850-6855 ◽  
Author(s):  
Titik Nuryastuti ◽  
Henny C. van der Mei ◽  
Henk J. Busscher ◽  
Susi Iravati ◽  
Abu T. Aman ◽  
...  
Keyword(s):  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Antimicrobial Agents ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Pcr Analysis ◽  
Minimal Bactericidal Concentration ◽  
Cinnamon Oil ◽  
Broth Microdilution Method

ABSTRACT Staphylococcus epidermidis is notorious for its biofilm formation on medical devices, and novel approaches to prevent and kill S. epidermidis biofilms are desired. In this study, the effect of cinnamon oil on planktonic and biofilm cultures of clinical S. epidermidis isolates was evaluated. Initially, susceptibility to cinnamon oil in planktonic cultures was compared to the commonly used antimicrobial agents chlorhexidine, triclosan, and gentamicin. The MIC of cinnamon oil, defined as the lowest concentration able to inhibit visible microbial growth, and the minimal bactericidal concentration, the lowest concentration required to kill 99.9% of the bacteria, were determined using the broth microdilution method and plating on agar. A checkerboard assay was used to evaluate the possible synergy between cinnamon oil and the other antimicrobial agents. The effect of cinnamon oil on biofilm growth was studied in 96-well plates and with confocal laser-scanning microscopy (CLSM). Biofilm susceptibility was determined using a metabolic 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Real-time PCR analysis was performed to determine the effect of sub-MIC concentrations of cinnamon oil on expression of the biofilm-related gene, icaA. Cinnamon oil showed antimicrobial activity against both planktonic and biofilm cultures of clinical S. epidermidis strains. There was only a small difference between planktonic and biofilm MICs, ranging from 0.5 to 1% and 1 to 2%, respectively. CLSM images indicated that cinnamon oil is able to detach and kill existing biofilms. Thus, cinnamon oil is an effective antimicrobial agent to combat S. epidermidis biofilms.

scholarly journals Ovule Development and in Planta Transformation of Paphiopedilum Maudiae by Agrobacterium-Mediated Ovary-Injection

2020 ◽  
Vol 22 (1) ◽  
pp. 84
Author(s):  
Bai-Xue Luo ◽  
Li Zhang ◽  
Feng Zheng ◽  
Kun-Lin Wu ◽  
Lin Li ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Developmental Stages ◽  
Embryo Sac ◽  
Mature Embryo ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Pcr Analysis ◽  
In Planta Transformation ◽  
In Planta ◽  
Hygromycin Selection

In this paper, the development of the Paphiopedilum Maudiae embryo sac at different developmental stages after pollination was assessed by confocal laser scanning microscopy. The mature seeds of P. Maudiae consisted of an exopleura and a spherical embryo, but without an endosperm, while the inner integument cells were absorbed by the developing embryo. The P. Maudiae embryo sac exhibited an Allium type of development. The time taken for the embryo to develop to a mature sac was 45-50 days after pollination (DAP) and most mature embryo sacs had completed fertilization and formed zygotes by about 50–54 DAP. In planta transformation was achieved by injection of the ovaries by Agrobacterium, resulting in 38 protocorms or seedlings after several rounds of hygromycin selection, corresponding to 2, 7, 5, 1, 3, 4, 9, and 7 plantlets from Agrobacterium-mediated ovary-injection at 30, 35, 42, 43, 45, 48, 50, and 53 DAP, respectively. Transformation efficiency was highest at 50 DAP (2.54%), followed by 2.48% at 53 DAP and 2.45% at 48 DAP. Four randomly selected hygromycin-resistant plants were GUS-positive after PCR analysis. Semi-quantitative PCR and quantitative real-time PCR analysis revealed the expression of the hpt gene in the leaves of eight hygromycin-resistant seedlings following Agrobacterium-mediated ovary-injection at 30, 35, 42, 43, 45, 48, 50, and 53 DAP, while hpt expression was not detected in the control. The best time to inject P. Maudiae ovaries in planta with Agrobacterium is 48-53 DAP, which corresponds to the period of fertilization. This protocol represents the first genetic transformation protocol for any Paphiopedilum species and will allow for expanded molecular breeding programs to introduce useful and interesting genes that can expand its ornamental and horticulturally important characteristics.

scholarly journals Study of the Adhesion of Silicate-Based Coating Formulations on a Wood Substrate

Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 61
Author(s):  
Arnaud Maxime Cheumani Yona ◽  
Jure Žigon ◽  
Sebastian Dahle ◽  
Marko Petrič
Keyword(s):  
Adhesion Strength ◽  
Laser Scanning ◽  
Beech Wood ◽  
Attenuated Total Reflection ◽  
Solid Particles ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Wood Substrate ◽  
Mechanical Anchoring ◽  
Coating Formulations

Silicate coatings are environmentally friendly inorganic-based products that have long been used for mineral substrates and protection of steel against corrosion. The development and acceptance of these coatings in the wood sector require some adjustments in formulations or special preparation of the surface to be coated to obtain durable finishes. In this work, the adhesion of various silicate-based formulations to a beech wood substrate (Fagus sylvatica L.), was assessed with the main objective to study relevant parameters and potential improvements. Adhesion strength was determined by pull-off and cross-cut tests. Other coating properties such as scratch, impact, and water resistance were also determined. Surface roughness and interface were analyzed using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM), and coating curing was studied by attenuated total reflection-infrared spectroscopy (ATR FTIR). The results showed that adhesion was highly dependent on formulation, penetration of the coatings into wood, and mechanical anchoring. Increasing the content of solid particles in the coating formulations or adding a polyol (glycerol, xylose), which probably acted as a coalescent, considerably decreased the adhesion strength, probably by blocking penetration into the wood by forming aggregates. Adhesion was improved by pre-mineralization of the surface, and substitution of a part of the potassium silicate binder with potassium methyl siliconate reduced the formation of cracks caused by dimensional instability of the wood.

scholarly journals Antimicrobial and Anticorrosion Activity of a Novel Composite Biocide against Mixed Bacterial Strains in Taiwanese Marine Environments

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6156
Author(s):  
Soul-Yi Chang ◽  
Shih-Yen Huang ◽  
Yu-Ren Chu ◽  
Shun-Yi Jian ◽  
Kai-Yin Lo ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Laser Scanning ◽  
Electrochemical Impedance ◽  
Laser Scanning Microscopy ◽  
304 Stainless Steel ◽  
Single Type ◽  
Confocal Laser ◽  
Subtropical Climate ◽  
Marine Environments ◽  
Bacterial Strains

Taiwan is an island with a humid subtropical climate. The relatively warm seawater results in biofouling of the surfaces of marine facilities. Biocide application is a common practice for combating and eliminating adhesive fouling. However, a single type of biocide may have limited antimicrobial effects due to the relatively high microbial diversity in marine environments. Therefore, applying a mixture of various biocides may be necessary. In this study, the antimicrobial and anticorrosion properties of a newly designed composite biocide, namely a combination of thymol and benzyldimethyldodecylammonium chloride, were investigated by applying the biocide to 304 stainless steel substrates immersed in inocula containing bacterial strains from Tamsui and Zuoying harbors. The ability of 3TB and 5TB treatments to prevent sessile cells and biofilm formation on the 304 stainless steel coupon surface was determined through scanning electron microscopy investigation. In addition, confocal laser scanning microscopy indicated that the 5TB treatment achieved a greater bactericidal effect in both the Tamsui and Zuoying inocula. Moreover, electrochemical impedance spectroscopy revealed that the diameter of the Nyquist semicircle was almost completely unaffected by Tamsui or Zuoying under the 5TB treatment. Through these assessments of antimicrobial activity and corrosion resistance, 5TB treatment was demonstrated to have superior bactericidal activity against mixed strains in both southern and northern Taiwanese marine environments.

scholarly journals Inhibition of Cronobacter Sakazakii Biofilm Formation and Expression of Virulence Factors by Coenzyme Q0

2020 ◽  
Author(s):  
Ning Guan ◽  
Yiqi Shi ◽  
Haoyu Tong ◽  
Yanpeng Yang ◽  
Jiahui Li ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Laser Scanning ◽  
Coenzyme Q ◽  
Polymerase Chain Reaction Analysis ◽  
Laser Scanning Microscopy ◽  
Raw 264.7 Cells ◽  
Confocal Laser ◽  
Dependent Manner ◽  
Cronobacter Sakazakii ◽  
And Control

Abstract Objectives：Here, we investigated the inhibitory effects of coenzyme Q0 (CoQ0) on biofilm formation and the expression of virulence genes by Cronobacter sakazakii. Results：We found that the minimum inhibitory concentration of CoQ0 against C. sakazakii strains ATCC29544 and ATCC29004 was 100 μg/mL, while growth curve assays showed that sub-inhibitory concentrations (SICs) of CoQ0 for both strains were 6.4, 3.2, 1.6 and 0.8 μg/mL. Assays exploring the inhibition of specific biofilm formation showed that SICs of CoQ0 inhibited biofilm formation by C. sakazakii in a dose-dependent manner, which was confirmed by scanning electron microscopy and confocal laser scanning microscopy analyses. CoQ0 inhibited the swimming and swarming motility of C. sakazakii and reduced its ability to adhere to and invade HT-29 cells. In addition, CoQ0 impeded the ability of C. sakazakii to survive and replicate within RAW 264.7 cells. Finally, real time polymerase chain reaction analysis confirmed that nine C. sakazakii genes associated with biofilm formation and virulence were down-regulated in response to CoQ0 treatment. Conclusion：Overall, our findings suggest that CoQ0 is a promising antibiofilm agent and provide new insights for the prevention and control of infections caused by C. sakazakii.

scholarly journals Application of Teeth Whitening LED for Prevention of Dental Caries : Antimicrobial Photodynamic Therapy Approach

2020 ◽  
Vol 47 (1) ◽  
pp. 70-77
Author(s):  
Choa Park ◽  
Howon Park ◽  
Juhyun Lee ◽  
Hyunwoo Seo ◽  
Siyoung Lee
Keyword(s):  
Photodynamic Therapy ◽  
Laser Scanning ◽  
Light Emitting Diode ◽  
Antimicrobial Effect ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Control Group ◽  
Antimicrobial Photodynamic Therapy ◽  
Group Dynamic ◽  
Light Emitting

The present study is aimed to assess the effect of antimicrobial photodynamic therapy (aPDT) on <i>Streptococcus mutans</i> biofilm through teeth whitening light emitting diode (LED).<br/>Planktonic and dynamic biofilm state cultures of <i>S. mutans</i> were used. Erythrosine 20 μM/L was used as the photosensitizer. Irradiation was performed by exposing cultures to clinic and homecare whitening LEDs for 15 minutes. The viability was measured through Colony Forming Unit counts and confocal laser scanning microscopy.<br/>aPDT using whitening LEDs and erythrosine significantly decreased the CFU count of <i>S. mutans</i> compared to that in the control group. Dynamic biofilm group showed more resistant features to aPDT compared with planktonic state. Clinic and homecare whitening LED device showed similar antimicrobial effect.<br/>The whitening LED, which could irradiate the entire oral arch, showed a significant photodynamic effect on cariogenic <i>S. mutans</i> biofilm. aPDT mediated by erythrosine and LEDs used for teeth whitening exhibited promising antimicrobial activity.

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