Effects of ferulic acid combined with light irradiation on deoxynivalenol and its production in Fusarium graminearum

This study aimed to investigate the effects of ferulic acid (FA), a natural phenolic phytochemical, in combination with light irradiation at three wavelengths (365, 385 and 405 nm) on the concentration and toxicity of deoxynivalenol (DON), a mycotoxin produced by Fusarium graminearum. Moreover, this study examined the influence of the combination treatment on DON production in the cultured fungus. FA activated by light at a peak wavelength of 365 nm exhibited the most effective decrease in DON concentration of the tested wavelengths; a residual DON ratio of 0.23 at 24 h exposure was observed, compared with the initial concentration. The reduction in DON using 365-nm light was dependent on the concentration of FA, with a good correlation (r2 = 0.979) between the rate constants of DON decrease and FA concentration, which was confirmed by a pseudo-first-order kinetics analysis of the photoreaction with different FA concentrations (50 400 mg/L) for 3 h. The viability of HepG2 cells increased by 56.7% following in vitro treatment with a mixture containing the photoproducts obtained after treatment with 20 mg/L DON and 200 mg/L FA under 365-nm irradiation for 6 h. These results suggested that the photoreaction of FA under 365-nm irradiation induces the detoxification of DON through degradation or modification of DON. The antifungal effects of the combination (FA and 365-nm light) on F. graminearum were investigated. Conidia treated with the combination did not show additive or synergistic inhibition of fungal biomass and DON production in 7-day cultivated fungal samples compared with samples after single treatment. However, successive treatment, composed of 90 min irradiation at 365 nm and then treatment with 200 mg/L FA for 90 min in the dark, suppressed fungal growth and DON yield to 70% and 25% of the untreated sample level, respectively. This photo-technology involving the two treatment methods of 365-nm irradiation and FA addition as a food-grade phenolic acid in combination or successively, can aid in developing alternative approaches to eliminate fungal contaminants in the fields of environmental water and agriculture. However, further research is required to explore the underlying mechanisms of DON decontamination and its biosynthesis in F. graminearum.


Plasma-Assisted Annealing of Pt-Doped Rutile TiO2 Nanoparticles for Enhanced Decomposition and Bacterial Inactivation under General Lighting

Journal of Vacuum Science and Technology. B, Nanotechnology & Microelectronics : Materials, Processing, Measurement, & Phenomena : JVST B


Porcine embryo development and inactivation of microorganisms after ultraviolet-C irradiation at 228 nm

It is important to prevent contamination inside the incubator as a method of preventing microbial infections during the embryo culture. In the present study, we examined the effects of ultraviolet-C (UV-C) irradiation, used for microorganism inactivation, on embryo development and the growth of bacteria, including Escherichia coli and Staphylococcus aureus, and the fungus Cladosporium cladosporioides. In the embryo irradiation experiment, we examined the effects of the plastic lid of the culture dish, irradiation distances (10, 20, and 25 cm), and different irradiation wavelengths (228 and 260 nm) during embryo culture for 7 days on the development and quality of porcine in vitro-fertilized embryos. None of the embryos cultured in dishes without plastic lids developed into blastocysts after irradiation with 228 nm UV-C. When porcine embryos were cultured in a culture dish with lids, the 228 nm UV-C irradiation decreased blastocyst formation rates of the embryos but not their quality, irrespective of the UV-C irradiation distance. Moreover, irradiation with 260 nm UV-C, even with plastic lids, had more detrimental effects on embryo development than irradiation with 228 nm UV-C. Investigation of the inactivating effects of UV-C irradiation at 228 nm and 260 nm on the growth of the bacteria and fungus showed that 260 nm UV-C reduced the viability to a greater extent than 228 nm UV-C. Moreover, the disinfection efficacy for the bacteria increased when the irradiation duration increased and the distance decreased. In conclusion, porcine embryos can develop into blastocysts without loss of quality even after continuous long-duration irradiation (7 days) with 228 nm UV-C, which can inactivate the growth of bacteria and the tested fungus; however, the development rate of the embryo is reduced.


Remote Bactericidal Effect of Anatase TiO2 Photocatalytic Nanoparticles Annealed with Low-Temperature O2 Plasma

The remote bactericidal effect of TiO photocatalyst, i.e., the bactericidal effect away from the photocatalyst, was successfully achieved using a humidified airflow. The TiO photocatalyst used was anatase-type TiO nanoparticles (NPs) annealed with a low-temperature O plasma. For comparison, anatase-type TiO NPs annealed in the air were used. The bacteria, Bacillus subtilis, were placed away from the TiO NPs. The plasma-assisted-annealed TiO NPs significantly inactivated 99% of the bacterial cells in 5 h, whereas the pristine and air-annealed TiO NPs inactivated 88-90% of the bacterial cells. The remote bactericidal effect of plasmaassisted-annealed TiO NPs would be attributed to a larger amount of HO molecules traveled by the airflow from the TiO NPs. The molecules were generated by chemically reacting more photoexcited carriers on the TiO surface with HO and O in the airflow. These photoexcited carriers originated from more oxygen-based species adsorbed and more oxygen vacancies introduced on the TiO surface by the plasma-assisted-annealing.


Bactericidal Effects of Low-Temperature Atmospheric-Pressure Air Plasma Jets with No Damage to Plant Nutrient Solutions


Antimicrobial action of phenolic acids combined with violet 405-nm light for disinfecting pathogenic and spoilage fungi

The aim of this study is to investigate the fungicidal spectrum of six phenolic-cinnamic and -benzoic acid derivatives using four fungi, Aspergillus niger, Cladosporium cladosporioides, Trichophyton mentagrophytes and Candida albicans, in a photocombination system with violet 405-nm light. This is the first study to examine the fungicidal mechanism involving oxidative damage using the conidium of A. niger, as well as an assessment of cellular function and chemical characteristics. The results of the screening assay indicated that ferulic acid (FA) and vanillic acid (VA), which possess 4-hydroxyl and 3-methoxy groups in their phenolic acid structures, produced synergistic activity with 405-nm light irradiation. FA and VA (5.0 mM) significantly decreased the viability of A. niger by 2.4 to 2.6-logs under 90-min irradiation. The synergistic effects were attenuated by the addition of the radical scavenger dimethyl sulfoxide. Generation of reactive oxygen species (ROS), such as hydrogen peroxide and hydroxyl radicals, were confirmed in the phenolic acid solutions tested after irradiation with colorimetric and electron spin resonance analyses. Adsorption of FA and VA to conidia was greater than other tested phenolic acids, and produced 1.55- and 1.85-fold elevation of intracellular ROS levels, as determined using an oxidant-sensitive probe with flow cytometry analysis. However, cell wall or membrane damage was not the main mechanism by which the combination-induced fungal death was mediated. Intracellular ATP was drastically diminished (5% of control levels) following combined treatment with FA and light exposure, even under a condition that produced negligible decreases in viability, thereby resulting in pronounced growth delay. These results suggest that the first stage in the photofungicidal mechanism is oxidative damage to mitochondria or the cellular catabolism system associated with ATP synthesis, which is a result of the photoreaction of phenolic acids adsorbed and internalized by conidia. This photo-technology in combination with food-grade phenolic acids can aid in developing alternative approaches for disinfection of pathogenic and spoilage fungi in the fields of agriculture, food processing and medical care.

Journal of Photochemistry and Photobiology B: Biology


Antifungal action of the combination of ferulic acid and ultraviolet-A irradiation against Saccharomyces cerevisiae

Aims To examine the antifungal action of photocombination treatment with ferulic acid (FA) and ultraviolet-A (UV-A) light (wavelength, 365 nm) by investigating associated changes in cellular functions of Saccharomyces cerevisiae. Methods and Results When pre-incubation of yeast cells with FA was extended from 0.5 to 10 min, its photofungicidal activity increased. Flow cytometry analysis of stained live and dead cells revealed that 10-min UV-A exposure combined with FA (1 mg ml-1) induced a ~ 99.9% decrease in cell viability although maintaining cell membrane integrity when compared with pre-exposure samples. When morphological and biochemical analysis were performed, treated cells exhibited an intact cell surface and oxidative DNA damage similar to control cells. Photocombination treatment induced cellular proteins oxidation, as shown by 2.3-fold increasing in immunostaining levels of ~49-kDa carbonylated proteins compared with pre-irradiation samples. Pyruvate kinase 1 (PK1) was identified by proteomics analysis as a candidate protein whose levels was affected by photocombination treatment. Moreover, intracellular ATP levels decreased following FA treatment both in darkness and with UV-A irradiation, thus suggesting a possible FA-induced delay in cell growth. Conclusions FA functions within the cytoplasmic membrane; addition of UV-A exposure induces increased oxidative modifications of cytosolic proteins such as PK1, which functions in ATP generation, without causing detectable genotoxicity, thus triggering inactivation of yeast cells. Significance and Impact of Study Microbial contamination is a serious problem that diminishes the quality of fruits and vegetables. Combining light exposure with food-grade phenolic acids such as FA is a promising disinfection technology for applications in agriculture and food processing. However, the mode of photofungicidal action of FA with UV-A light remains unclear. This study is the first to elucidate the mechanism using S. cerevisiae. Moreover, proteomics analyses identified a specific cytosolic protein, PK1, which is oxidatively modified by photocombination treatment.


Ultraviolet Light-Emitting Diode (UV-LED) Sterilization of Citrus Bacterial Canker Disease Targeted for Effective Decontamination of Citrus Sudachi Fruit


Effects of violet-blue light-emitting diode on controlling bacterial contamination in boiled young sardine

The aim of this study was to evaluate bacterial decontamination of boiled young sardine by treatment with violet-blue light followed by cooling storage of the irradiated boiled sardine. Viable cell count in the samples was evaluated after irradiation with four types of violet-blue light-emitting diodes (LEDs; peak wavelength at 405, 412, 421 or 455 nm) and subsequent cooling storage for two days. LED (405 nm) exhibited bactericidal and growth suppression effects. The irradiation gave a 47% bactericidal rate in comparison with no irradiation samples (control) and the two-day storage suppressed the increase in cell counts to 24%, while the rate of increase was 545% for the control. Integrated viability (IV) based on growth delay analysis was estimated after irradiation of four isolates from boiled sardine with 405 nm light. The irradiation caused growth delay against all isolates, resulting in smaller IV values for three isolates compared to those viabilities estimated from colony forming units. Exposure (405 nm) at 432 J/cm2 fluence resulted in a decrease in water content, resulting in an increase in salinity of the samples. This study demonstrated the advantages of light emitting a narrow violet region as a non-thermal disinfection technology in the processing and storage of boiled sardines.


Photocatalytic Activity Enhancement of Anatase/Rutile-Mixed Phase TiO2 Nanoparticles Annealed with Low-Temperature O2 Plasma

Physica Status Solidi (A) Applications and Materials Science


Therapeutic Effect and Mechanism of Action of Low-molecular-weight Whey Protein Capable of Activating Macrophages in Bovine Mastitis

Bovine mastitis is caused by the invasion and propagation of pathogenic microorganisms into the udder and mammary gland tissues of cattle. In this study, the therapeutic effect of a low-molecular-weight whey protein (LMW-WP) on bovine mastitis was evaluated. LMW-WP was orally, intraperitoneally, and vaginally administered to bovine with mastitis. The number of somatic cells in milk was measured 24 h before the administration of LMW-WP. The effect of LMW-WP on cytokine production was measured with a microarray that evaluates the expression of cytokines. In the group that received 1,000 mg intraperitoneally, the somatic cell count was reduced to less than 400,000 at the shipment standard value in three of the four udders, indicating 75% efficacy. The group that received 1,000 mg by vaginal administration showed 67% efficacy. It was confirmed that LMW-WP increased the production of cytokines such as IL-5, IL-6, IL-9, IL-12, MCP-1, and VEGF in mouse macrophage cells, but it did not show any antibacterial activity. LMW-WP may be an effective therapeutic agent for bovine mastitis.


Effects of Nonequilibrium Atmospheric-Pressure O2 Plasma-Assisted Annealing on Anatase TiO2 Nanoparticles


Phylogenetic Analysis of Bacterial Isolates from Boiled Sardine and the Effect of Ultraviolet Light-Emitting Diode Light on Them

釜揚げしらす由来分離株の系統解析および釜揚げしらすとその分離株に対する紫外線LEDの影響

Journal of Antibacterial and Antifungal Agents


Bactericidal action of ferulic acid with ultraviolet-A light irradiation

The bactericidal activity of ferulic acid (FA) against various microorganisms was remarkably enhanced by ultraviolet-A (UV-A) irradiation (wavelength, 365 nm). However, the bactericidal mechanism in the photo-combination system has not been evaluated. In the present study, this combined treatment was characterized by investigating associated changes in cellular functions of Escherichia coli, including assessments of respiratory activity, lipid peroxidation, membrane permeability, and damage to DNA and the cell surface. FA adsorbed onto and was incorporated into bacterial membranes, and the affinity resulted in decreased respiratory activity and enhanced lipid peroxidation in the cytoplasmic membrane with low-fluence (1.0 J/cm2) UV-A irradiation. Flow cytometry analysis revealed that additional exposure (8 J/cm2) combined with FA (1 mg/mL) induced increased cell permeability, yielding a 4.8-log decrease in the viable cell count. Morphologically, the treated cells exhibited a bacterial membrane dysfunction, producing many vesicles on the cell surface. However, despite this effect on the cell surface, plasmid DNA transformed into FA-treated E. coli maintained supercoiled integrity with negligible DNA oxidation. Our data strongly suggested that FA functions inside and outside the bacterial membrane; UV-A exposure in the presence of FA then causes increased oxidative modification and subsequent disruption of the bacterial membrane, without causing detectable genotoxicity.


Inactivation of foodborne pathogenic and spoilage microorganisms using ultraviolet-A light in combination with ferulic acid

The low energy of UV-A (315 400 nm) is insufficient for disinfection. To improve UV-A disinfection technology, the effect of ferulic acid (FA) addition on inactivation by UV-A light-emitting diode (LED) light (350 385 nm) was evaluated in the eliminating of suspensions of various food spoilers and pathogens (seven bacteria and four fungi). Photoantimicrobial assays were performed at FA concentrations below the MIC. The MIC of the isomerized FA, consisting of 93% cis-form and 7% trans-form, was very similar to that of the commercially available FA (trans-form). Irradiation with UV-A (1.0 J cm-2) in the presence of 100 mg l-1 FA resulted in enhanced reducing of all of the tested bacterial strains. A combination of UV-A (10 J cm-2) and 1000 mg l-1 FA resulted in enhanced reducing of Saccharomyces cerevisiae and one of the tested filamentous fungi. These results demonstrated that the combination of a short-term application of UV-A and FA at a low concentration yielded synergistic enhancement of antimicrobial activity, especially against bacteria.


Identification and Characterization of a 25 kDa Protein That Is Indispensable for the Efficient Saccharification of Eisenia bicyclis in the Digestive Fluid of Aplysia kurodai

The digestive fluid of the sea hare Aplysia kurodai can liberate approximately 2.5 mg of glucose from 10 mg of dried Eisenia bicyclis powder. Although laminaran, a major storage polysaccharide in E. bicyclis, is easily digested to glucose by the synergistic action of the 110 and 210 kDa A. kurodai -glucosidases (BGLs), glucose is not liberated from E. bicyclis by direct incubation with these BGLs. To clarify this discrepancy, we searched for an Eisenia hydrolysis enhancing protein (EHEP) in the digestive fluid of A. kurodai. A novel 25 kDa protein that enhances E. bicyclis saccharification by -glucosidases was purified to a homogeneous state from the digestive fluid of A. kurodai, and its cDNA was cloned from total cDNAs reverse-transcribed from hepatopancreas total RNA. The E. bicyclis extract strongly inhibited BGLs, suggesting some compound within this brown alga functioned as a feeding deterrent. However, when E. bicyclis was incubated with BGLs in the presence of EHEP, glucose production was markedly increased. As E. bicyclis is rich in phlorotannin, which are only found in brown algae, our study suggested that these compounds are the main BGL inhibitors in E. bicyclis extract. EHEP protects BGLs from phlorotannin inhibition by binding to phlorotannins and forming an insoluble complex with phloroglucinol and phlorotannins. These findings indicated that EHEP plays a key role in the saccharification of brown seaweeds containing phlorotannins in the digestive fluid of A. kurodai. This is the first report of EHEP as a phlorotannin-binding protein that protects BGLs from inhibition.


Improved photobactericidal activity of ultraviolet-A light in combination with isomerizable p-coumaric acid derivatives


Synergistic photobactericidal activity based on ultraviolet-A irradiation and ferulic acid derivatives

Ultraviolet-A (UV-A)-mediated bactericidal activity was enhanced by combined treatment with trans-ferulic acid (trans-FA, compound 1) or its derivatives. Derivative compounds 4 and 10 contain a phenyl group or an L-tyrosine HCl tert-butyl ester, respectively, linked to the carboxyl group of trans-FA. Of the three compounds, 10 exhibited the highest synergistic activity in a photobactericidal assay based on treating Escherichia coli with a derivative compound and UV-A irradiation (wavelength 350-385 nm). Inactivation of viable cells at a 4.9 J/cm(2) UV-A fluence increased from 1.90 to 5.19 logs in the presence of 10 (100 μM); a 4.95-log inactivation was achieved with 10 (5 μM) and a 7.4 J/cm(2) UV-A fluence. Addition of antioxidants significantly suppressed photosynergistic bactericidal activity, suggesting that reactive oxygen species (ROS) are involved in the combined bactericidal mechanism. Flow cytometry revealed that combined treatment with UV-A and compound 10, which showed the highest photobactericidal activity, generates an excess of oxidative radicals in bacterial cells. The bactericidal activity of compound 10 may be due to electrostatic interaction between the molecule's cationic moiety and the cell surface, followed by amplification of ROS generation in the cells. This article is protected by copyright. All rights reserved.


Effect of polyphenols on reactive oxygen species production and cell growth of human dermal fibroblasts after irradiation with ultraviolet-A light

Ultraviolet-A (UV-A) can damage microbes by generating reactive oxygen species (ROS), singlet oxygen, superoxides, hydrogen peroxide and hydroxyl radicals. These species readily react with lipids, proteins, DNA and other constituents of cells, leading to oxidative deterioration and the eventual death of the microbe. However, the oxidative ability of these reactive species also harms the viability of mammalian cells such as fibroblasts and keratinocytes, as they cause both acute and chronic damage, photo-aging, and photo-carcinogenesis. This study describes a UV-A treatment that does not affect the viability or growth of human neonate dermal fibroblasts, as determined by examining the post-irradiation cell density after the addition of polyphenols as antioxidants. The results demonstrate the possible wide applicability of UV-A sterilization. The potency of polyphenols for attenuating UV-A-induced ROS generation in cells was tested using (+)-catechin hydrate, (-)- epigallocatechin gallate hydrate, morin hydrate, quercetin hydrate and resveratrol. The lowest concentration of polyphenols required to reduce ROS by 50% in cells upon exposure to a dose of 15 J cm-2 was determined and defined as its IC50. Pre-treatment with morin hydrate at its IC50 allowed cells irradiated with 5.0 J cm-2 UV-A to recover to the level of the specific growth rate of cells incubated without UV-A irradiation. However, the growth rate of cells exposed to 15 J cm-2 UV-A irradiation was scarcely influenced by co-incubation with morin hydrate; this dose of UV-A also suppressed cell growthcompletely in the absence of morin hydrate, although co-incubation resulted in no decrease in cell viability. This study demonstrates the potential of polyphenols for protecting both the viability of cells and their ability to proliferate from damage caused by UV-A-irradiation.


Trehalose suppresses antibody aggregation during the culture of Chinese hamster ovary cells

The aggregation of therapeutic antibodies during the manufacturing process is problematic because of the potential risks posed by the aggregates, such as an unexpected immune response. One of the hallmark effects of trehalose, a disaccharide consisting of two alpha-glucose units, is as a chemical chaperone with anti-aggregation activity. In this study, Chinese hamster ovary (CHO) cell line producing a diabody-type bispecific antibody were cultured in medium containing trehalose and the aggregation of the secreted proteins during the culture process was analyzed. An analysis of the various forms of the antibody (monomeric, dimeric, and large aggregates) showed that trehalose decreased the relative content of large aggregates by two thirds. The aggregation kinetics indicated that trehalose directly inhibited the polymerization and aggregation steps in a nucleation-dependent aggregation mechanism. Moreover, both specific and volumetric antibody production were increased in CHO cells cultured in trehalose-containing medium. Thus, the addition of trehalose to recombinant CHO cell cultures would offer a practical strategy for quality improvement in the production of therapeutic antibodies.

Journal of Bioscience and Bioengineering


Synergistic antimicrobial activity based on the combined use of a gemini-quaternary ammonium compound and ultraviolet A light

This study examined the utility of synergistic disinfection employing a gemini-quaternary ammonium salt (a gemini-QUAT, namely 3,3'-(2,7-dioxaoctane)bis(1-decylpyridinium bromide)), as an organic biocide in combination with irradiation by an ultraviolet-A (UV-A) light-emitting diode (LED) with a peak wavelength of 365nm. The combined system represents a novel disinfection method utilizing facilitated in situ oxidation depending on overproduction of reactive oxygen species (ROS) triggered by the initial action of the gemini-QUAT on the bacterial membrane. We demonstrate that this combination decreased the viability of pathogenic bacteria in a significant and rapid manner, and depended on doses of the gemini-QUAT and the fluence: the viability of Escherichia coli was reduced by greater than 5.0-logs by the combination procedure, but the decrease in viability was only 2.3-logs for exposure to UV at the same fluence dose in the absence of the gemini-QUAT. Adding catalase as a radical scavenger decreased bacterial inactivation by the combined disinfection procedure. Flow cytometric analysis indicated superoxide and hydrogen peroxide overproduction within cells treated with the combined disinfection procedure. The excessive superoxide, detected only in the combined system, appeared to be generated by the action of the gemini-QUAT at the bacterial membrane, leading to excessive and rapid generation of ROS in the system. Our data strongly suggested that this ROS promoted bacterial membrane peroxidation during initial treatment by the combination method, resulting in increased oxidative modification of DNA. These oxidative reactions may play an important role in the efficacy of this disinfection procedure.

Journal of Photochemistry and Photobiology B: Biology


Synthesis of thiazole derivatives and evaluation of their antiamoebic activity and cytotoxicity

Five ethyl (5-alkyl-2-amino-1,3-thiazol-4-yl) acetates (designated compounds 4a-e) incorporating octyl, decyl, dodecyl, tetradecyl, and hexadecyl alkyl chains, respectively, were prepared by reacting 4-alkyl-4-bromo-3-oxobutyric acid ethyl esters (3a-e) with thiourea in dried acetonitrile. Compounds 3a-e were synthesized by reacting alkylated ethyl acetoacetates with bromine. The newly synthesized compounds were characterized by mass spectrometry, NMR, and elemental analysis. Compounds 4a-c demonstrated good in vitro antiamoebic activity against Acanthamoeba polyphaga exposed to 10 mg L(-1) for 6 h at 28 °C. Compound 4b showed the highest antiamoebic activity among the tested compounds, comparable to that of chlorhexidine dihydrochloride (CHX), decreasing the number of viable cells to below the detection limit of 1 cell mL(-1). The activity of compounds 4a and 4c was similar to that of the commercial antifungal agent fluconazole (Flu). The cytotoxic and hemolytic activity of the compounds was assayed against human neonate dermal fibroblasts and sheep erythrocytes, respectively. Compounds 4a-c were less cytotoxic than Flu and CHX. Our results suggest that compound 4b, which is composed of a 2-amino-thiazole attached to a decyl group and an ethyl ester moiety, is a particularly safe and effective alternative amoebicidal agent.


Synthesis and biological activity of thiazolyl-acetic acid derivatives as possible antimicrobial agents

5a-h, a series of (5-substituted-2-methyl-1,3-thiazole-4-yl) acetic acids as heterocyclic acetic acid derivatives, was designed and synthesized from ethyl acetoacetate. The synthesized compounds were screened for their antimicrobial activities against bacterial and fungal strains, and their characteristics were investigated by assays under various temperature and pH conditions. Cytotoxicity was evaluated with the use of sheep erythrocytes and human neonate dermal fibroblasts. Similarly, agents such as lauric acid 6 and parabens 7a-b, which are used as preservative agents for commercial cosmetics and detergents, were assayed for comparison. Although the structure of 5a is simple, comprising a thiazole attached with an octyl group and acetic acid moiety, the compound showed stronger and broader antibacterial and antifungal activities among the 5 series against the tested microbes other than gram-negative bacteria. Interestingly, 5a overcame the weak antifungal activity of parabens 7a-b. Also, the cytotoxicity of 5a was less than that of parabens 7a-b, especially to human dermal fibroblasts. These results suggest that thiazolyl-acetic acid 5a is a potentially effective biocide, and that it could be used as a preservative agent in commercially sold cosmetics and detergents, facilitated by the hydrophilic and charge properties of its carboxylic acid moiety.


Two routes of MexS-MexT-mediated regulation of MexEF-OprN and MexAB-OprM efflux pump expression in Pseudomonas aeruginosa

The NfxC-type mutant of Pseudomonas aeruginosa produces the MexEF-OprN efflux pump and down-regulates expression of the quorum-sensing-dependent efflux pump MexAB-OprM and production of virulence factors in the presence of an active transcriptional regulator, MexT. Consequently, these cells are resistant to chloramphenicol and hypersusceptible to β-lactam antibiotics. An upper negative regulator, MexS, has been assumed to inactivate MexT in wild-type strains, hence shutting down production of the MexEF-OprN pump. This observation was, however, reported in only one clinical strain and not confirmed in well-characterized laboratory strains. Moreover, it is not known whether MexS is involved in the quorum-sensing-dependent regulation of virulence factor production. To assess these issues, a plasmid carrying wild-type mexS was introduced into three NfxC-type mutants from laboratory strains, which carry an impaired mexS and unimpaired mexT. Unexpectedly, all the transformants produced an increased amount of MexEF-OprN proteins. Three clinical NfxC strains were similarly transformed and although MexEF-OprN was undetectable in two of these strains, one produced an increased amount of these proteins, similar to the laboratory strains. These results were interpreted to mean that P. aeruginosa takes two separate routes in MexT-mediated regulation of mexEF-oprN expression: the MexS-bypassed pathway and MexS-mediated pathway. On the other hand, the transformants of both the laboratory and clinically derived NfxC-type cells produced increased amounts of MexAB-OprM and virulence factors, suggesting that production of these proteins occurs via the MexS-mediated pathway.


Action of reactive oxygen species in the antifungal mechanism of gemini-pyridinium salts against yeast

We previously found that the gemini quaternary salt (gemini-QUAT) containing two pyridinium residues per molecule, 3,3'- (2,7-dioxaoctane) bis (1-decylpyridinium bromide) (3DOBP-4,10) , exerted fungicidal activity against Saccharomyces cerevisiae and caused respiration inhibition and the cytoplasmic leakage of ATP, magnesium, and potassium ions. Here, we investigated how the gemini-QUAT, 3DOBP-4,10, exerts more powerful antimicrobial activity than the mono-QUAT N-cetylpyridinium chloride (CPC) and examined the association between reactive oxygen species (ROS) and the antimicrobial mechanism. Antifungal assays showed that the activity of 3DOBP-4,10 against two yeasts, S. cerevisiae and Candida albicans, was significantly elevated under aerobic conditions, and largely reduced under anaerobic conditions (nitrogen atmosphere) . Adding radical scavengers such as superoxide dismutase, catalase and potassium iodide (KI) also decreased the fungicidal activity of 3DOBP-4,10 but negligibly affected that of CPC. We measured survival under static conditions and found that the rapid fungicidal profile of 3DOBP-4,10 was lost, whereas that of CPC was slightly affected in the presence of KI. Our results suggest that 3DOBP-4,10 exerts powerful antimicrobial activity by penetrating the cell wall and membrane, which then allows oxygen to enter the cells, where it participates in the generation of intracellular ROS. The activity could thus be attributable to a synergic antimicrobial combination of the disruption of organelle membranes by the QUAT and oxidative stress imposed by ROS.


Functionalization of MexT Enhances MexEF-OprN Expression to Overcome Its Repression by MvaT in Pseudomonas aeruginosa


Mutation in the sdeS gene promotes expression of the sdeAB efflux pump gene and multidrug resistance in Serratia marcescens

Serratia marcescens gained resistance to both biocides and antibiotics on expressing the SdeAB efflux pump, following exposure to increasingly higher concentrations of a biocide (H. Maseda et al., Antimicrob. Agents Chemother. 53:5230-5235, 2009). To reveal the regulatory mechanism of sdeAB expression, wild-type cells were subjected to transposon-mediated random mutagenesis, and a mutant with antibiotic resistance, which mimicked the phenotype of the previous biocide-resistant cells, was obtained. The transposon element was found in the chromosomal DNA downstream of the sdeAB operon. Sequencing revealed the presence of an open reading frame (ORF) encoding a protein with 159 amino acid residues that is highly similar to the BadM-type transcriptional repressor, designated sdeS. The level of sdeB::xylE reporter gene expression, undetectable in the wild-type cells, appeared to be fully comparable to that in the biocide-resistant cells. Nucleotide sequencing of the mutant revealed sdeS to have a single G-to-A base substitution at position 269 that converted Trp90 to a stop codon. Introduction of a plasmid-borne intact sdeS into the mutant cells and the biocide-resistant cells resulted in a reduction in sdeB::xylE reporter activity to an undetectable level. These results suggested that SdeS functions as a repressor of the sdeAB operon. It was concluded that the original biocide-resistant cells had an impaired sdeS and, therefore, a derepressed level of the SdeAB efflux pump.


The Quantitative Assay of Trophozoites and Cysts of Acanthamoeba by Applying ATP Measurement and the Establishment of an Amoebicidal Test Method

ATP測定法を利用したアカントアメーバの栄養体およびシストの定量評価と抗アメーバ性試験法の確立

栄養体およびシストアメーバを対象にした細胞内ATP抽出によるATP測定法を用いたアメーバ定量法を確立した．可溶性有機物を含まないPage's Amoeba Saline (PAS)培地で調製されるAcanthamoebaは，プロテオースペプトン-酵母エキス-グリシン-システイン(PYGC)液体培地で培養し，次に有機物量を1/2量とするPYGC液体培地で培養することにより調製された．アメーバ懸濁液を48穴マイクロプレートに分注し，浮遊(上清)および付着アメーバ由来のATP量を測定した．調整アメーバ数とATP量の間には明らかな直線関係を示し，算出される栄養体アメーバとシストアメーバ1細胞当たりのATP量は，それぞれ5.00×10-2 pmol， 8.50×10-3 pmolであった．本手法を用いたATP測定によれば，1生細胞まで検出可能であることも特徴であった．次に，このATP測定法によるアメーバ定量法を抗微生物剤の抗アメーバ活性試験に応用することを検討した．各薬剤接触後，形態観察とATP量測定により，形態変化とATP量変化に密な関係があることが認められた．これらの結果は，アメーバのATP評価にとっての操作法の基礎と抗アメーバ性標準試験法としての応用性を示した．

Journal of Antibacterial and Antifungal Agents, Japan


The Development of Gemini-Quaternary Ammonium Compound-Supported Inorganic-Organic Hybrids as Antimicrobial Materials

ジェミニ型第四アンモニウム化合物を担持させた無機-有機ハイブリッド抗菌剤の開発

Gemini型第四アンモニウム塩(gemini-QAC)である1,4-ビス[3,3-(1-デシルピリジニウム)メチルオキシ]ブタンジブロマイド(Hygenia)を含む3種類のQACを層状アルミノシリケートであるモンモリロナイト(MMT)の層間に担持した無機-有機ハイブリッドを合成した．合成したハイブリッドは，元素分析，粉体X線結晶回折，TG-DTAにより物性評価され，そしてQAC遊離パターンと抗菌活性を調べ，徐放的殺菌性能を明らかにした．さらに，Hygenia-MMTを含む塗料の薄膜は，Aspergillus niger胞子に対し，菌糸の成長を阻害した．


Mutational upregulation of a resistance-nodulation-cell division-type multidrug efflux pump, SdeAB, upon exposure to a biocide, cetylpyridinium chloride, and antibiotic resistance in Serratia marcescens

Serratia marcescens is an important opportunistic pathogen in hospitals, where quaternary ammonium compounds are often used for disinfection. The aim of this study is to elucidate the effect of a biocide on the emergence of biocide- and antibiotic-resistant mutants and to characterize the molecular mechanism of biocide resistance in Serratia marcescens. A quaternary ammonium compound-resistant strain, CRes01, was selected by exposing a wild-type strain of S. marcescens to cetylpyridinium chloride. The CRes01 cells exhibited 2- to 16-fold more resistance than the wild-type cells to biocides and antibiotics, including cetylpyridinium chloride, benzalkonium chloride, chlorhexidine gluconate, fluoroquinolones, tetracycline, and chloramphenicol, and showed increased susceptibilities to beta-lactam antibiotics and N-dodecylpyridinium iodide. Mutant cells accumulated lower levels of norfloxacin than the parent cells in an energized state but not in a de-energized state, suggesting that the strain produced a multidrug efflux pump(s). To verify this assumption, we knocked out a putative efflux pump gene, sdeAB, in CRes01 and found that the knockout restored susceptibility to most quaternary ammonium compounds and antibiotics, to which the CRes01 strain showed resistance. On the basis of these and other results, we concluded that S. marcescens gains resistance to both biocides and antibiotics by expressing the SdeAB efflux pump upon exposure to cetylpyridinium chloride.


The mode of the antifungal activity of gemini-pyridinium salt against yeast

The gemini quaternary salt (gemini-QUAT) containing two pyridinium residues per molecule, 3,3'-(2,7-dioxaoctane) bis (1-decylpyridinium bromide) (3DOBP-4,10), exerted fungicidal activity against Saccharomyces cerevisiae accompanied by respiration inhibition and the cytoplasmic material leakage of ATP, magnesium, and potassium ions. We previously found that gemini-QUAT exerted bacterioclastic action against Escherichia coli by causing the rapid and abundant leakage of turbid materials from the cells. In addition, the first stage of the bacterioclastic action was the leakage of magnesium ions, outer membrane protein E, ATP, and lipopolysaccharides. Here, we investigated how the gemini-QUAT 3DOBP-4,10 exerts fungicidal action against S. cerevislae. The results showed that that > or = 0.4 microM 3DOBP-4,10 stopped respiration and that > or = 3.0, 1.0 and 1.0 microM caused the leakage of cytoplasmic components ATP, magnesium and potassium ions, respectively. Scanning and transmission electron micrographs showed a preserved cell wall structure, whereas intracellular organelles were destroyed in cells incubated with 3DOBP-4,10. We postulated that 3DOBP-4,10 exerts its fungicidal action against S. cerevisiae not through cell wall destruction and protein leakage, but rather by penetrating the cell wall and disrupting the membranes of organelles.


銀担持アクリル繊維を含む抗菌紙の魚病原因細菌に対する殺菌特性

銀担持アクリル繊維を含む抗菌紙の魚病原因細菌に対する殺菌特性

銀担持アクリル繊維，ポリエステル，ポロプロピレンの3種混抄紙(izi)の魚病原因細菌に対する殺菌特性を明らかにした．iziは，アユ養殖場から分離された魚病原因細菌に対して強い殺菌力を有していた．また，iziの殺菌力は，一般細菌と魚病原因細菌を含むアユ養殖場のプール水の殺菌に有効であることを示した．


Antibacterial activity and characteristics of modified ferrite powder coated with a gemini pyridinium salt molecule

This report describes the synthesis of an antibacterial material consisting of a gemini quaternary ammonium salt (gemini-QUAT) immobilized on ferrite powder, and its antibacterial activity. A gemini-QUAT containing two pyridinium residues per molecule, 4,4'-[1,3-(2,2-dihydroxylmethyl-1,3-dithiapropane)]bis (1-octylpyridinium bromide), was immobilized on ferrite powder by a reaction between the hydroxyl group of the QUAT and trimethoxysilane. Immobilization of the gemini-QUAT on ferrite (F-gemini-QUAT) was confirmed when the dye, bromophenol blue, was released from F-gemini-QUAT-dye after contact between ferrite and the dye. Elemental analysis of the QUAT-ferrite determined the molar amount of QUAT on the ferrite. The antibacterial effect of the ferrite was investigated using a batch treatment system, and this effect was compared with that of another QUAT-ferrite (F-mono-QUAT) binding a mono-QUAT, which possesses one pyridinium residue, prepared by the same immobilization method as F-gemini-QUAT. Results indicated the F-gemini QUAT possessed a higher bactericidal potency and broader antibacterial spectrum compared to F-mono-QUAT. In addition, this study suggested that gemini-QUATs possessed high bactericidal potency without being influenced by immobilization to materials, and the antibacterial activity and characteristics of F-gemini-QUAT could be attributed to the unique structure of the immobilized gemini-QUAT.


Construction of a leftover bath water model for microbial testing

In this study, in order to construct a model of leftover bath water, we analyzed one hundred samples of used bath water samples which were provided by twenty-eight volunteer families. It appeared that the number of detected bacteria from such bath water was correlated closely with the number of bathers. Moreover, the pH, acidity, chemical oxygen demand (COD), ion, protein content of the leftover bath water were measured. The number of bathers had no connection with the pH, acidity, COD, and ion content of the leftover bath water. However, the protein content of the bath water correlated with the number of detected bacteria. Based on these results, the model of leftover bath water was constructed. Achromobacter xylosoxidans, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa were incubated with the model bath water as indices of bath water contamination. The number of incubated viable cells in the model bath water increased with increasing concentrations of casamino acid. Consequently, it was suggested that varying the concentration of casamino acid based on family size or contamination would be necessary in the efficient use of the constructed model of leftover bath water for microbial testing.


Synthesis and biological properties of gemini quaternary ammonium compounds,5,5'-[2,2'-(α,ω-polymethylnedicarbonyldioxy)diethyl]bis(3-alkyl-4-methylthiazolium iodide) and 5,5'- [2,2'-(ρ-phenylenedicarbonyldioxy)diethyl] bis(3-alkyl-4-methylthiazolium bromide)

We synthesized gemini quaternary ammonium compounds (gemini QACs) having two thiazolium moieties in a molecule, 5,5'-[2,2'-(alpha,omega-polymethylnedicarbonyldioxy)diethyl]bis(3-alkyl-4-methylthiazolium iodide) (5DEBT-m,n), on which the carbon number of the methylene chain linking the two thiazoles (m) is 2, 6 or 8 and that of the alkyl group (n) is 8, 10, 12, 14 or 16. 5,5'-[2,2'-(p-Phenylenedicarbonyldioxy)diethyl]bis(3-alkyl-4-methylthiazolium bromide) (5DEBT-P,n) was then synthesized, which is composed of a p-phenylene as the methylene spacer. For five gemini QAC series, in addition to the previously described 5DEBT-4,n to the four new compound series, their antimicrobial activities were determined. 5DEBT-m,10 and -P,10 exhibited a wide and strong bacteriostatic activity against gram-negative and -positive bacteria, fungi and then yeast in comparison with N-tetradecyl-5-(2-hydroxyethyl)-4-methylthiazolium iodide as a mono-QAC. The bactericidal activity of the 5DEBT series against Escherichia coli IFO 12713 and Staphylococcus aureus IFO 12732 was investigated on the basis of the effects of their alkyl chain length and their molecular hydrophobicity. It was found that the effect of theses factors on their activity significantly changes by the difference between the gram-negative and -positive bacteria. Although against the gram-negative bacterium, the change in the activity due to extension of the alkyl group for each compound affected the kind of methylene spacer, against the gram-positive bacterium, it was almost equal in spite of the methylene spacer. This result could be responsible for the bactericidal mechanism of the gemini QACs being influenced by the diversity of the steric structure participating in the methylene chain length and by the bacterium cell surface hydrophobicity.


Syntheses and antimicrobial activities of series of new bis-quaternary ammonium compounds

A series of new bis-quaternary ammonium compounds (bis-QACs), 4,4'-(2,9-dioxadecane) bis(1-alkylpyridinium bromide)s, 3,3'-(2,9-dioxadecane)bis(1-alkylpyridinium bromide)s and 3,3'-(2,7-dioxaoctane)bis(1-decylpyridinium bromide) was synthesized. The compounds were evaluated by their activities against bacteria, molds and yeasts; the activities were expressed as the minimum inhibitory concentrations (MIC) and/or the minimum bactericidal concentrations (MBC). Compound 4,4'-(2,9-dioxadecane) bis(1-decylpyridinium bromide) had MIC values which exceeded those of benzalkoniumchloride and thiabendazole. It was in vitro active against a broad spectrum of Gram-negative and Gram-positive bacteria, against yeasts and some molds, it had high solubility and thermal decomposition temperature. The relationships between structure and biological activity of the tested bis-QACs are discussed.


Antifungal characteristics of N,N'-hexamethylenebis (4-carbamoyl-1-decylpyridinium bromide)

A bis-quaternary ammonium compound (bis-QAC), N,N'-hexamethylenebis(4-carbamoyl-1decylpyridinium bromide) (D-38), exhibited a wide antifungal spectrum and a strong activity against sixteen strains of fungi including nine strains isolated from various kinds of food. The antifungal activity was higher than that of N-dodecylpyridinium Iodide, a typical mono-QAC, and that of the commonly used fungicide, 2-(4-thiazolyl) benzimidazole. The activity of D-38, however, was comparatively low when it was measured by the agar dilution method. It is considered that the hydrophobic D-38 molecules, having two long alkyl chains, interacted with the agar medium, and therefore showed lower activity results. On the other hand, the activity of D-38 against Aspergillus niger IFO 6342 was not significantly influenced by temperature, pH and the initial spore concentration. These results indicate that bis-QACs can exhibit a high antifungal activity whether or not the environmental conditions change.


Biological and physicochemical properties of gemini quaternary ammonium compounds in which the positions of a cross-linking sulfur in the spacer differ

Gemini型第四アンモニウム化合物(gemini QAC)の架橋構造のスルフィド結合の位置に着目した．メチレンスルフィド，エチレンジスルフィド，スルフィドがピリジン環に連結したgemini QACの3種のを合成し，抗菌活性，ヒト赤血球溶血毒性，界面活性能に関するスルフィド結合位置の影響について検討した．ピリジン環に連結したスルフィド結合を有する化合物は，抗菌力，溶血毒性，界面活性能いずれにおいても，他の2種薬剤よりも高いことが分かった．その強い抗菌力と溶血毒性は，スルフィド結合の共鳴効果によるアンモニウムカチオン電子密度の上昇，スルフィドがテトラメチレンスペーサ鎖両末端に存在することによるスペーサ鎖の高い伸縮性に起因した小さい分子占有面積，そして高い薬剤分子疎水性に寄与すると考え，スペーサ鎖の立体構造に影響し，スルフィドの位置がアンモニウムカチオン電子密度に影響を及ぼすと結論した．


Antimicrobial characteristics of bis-quaternary ammonium compounds possessing a p-phenylene group in their spacer chains

p-フェニレンスペーサにより連結された2つのピリジニウム塩から成るフェニレン-ビス型四アンモニウム化合物 (Ph-bis-QACs)の抗菌特性および構造活性相関についてメチレンスペーサ鎖により連結されたメチレン-ビス型四アンモニウム化合物(M-bis-QACs)と比較検討した．Ph-bis-QACsは，高い殺菌活性と広い抗菌スペクトルを示した．Ph-bis-QACsの抗菌活性は，M-bis-QACsのメチレンスペーサ鎖をp-フェニレンスペーサ鎖に変換することによってM-bis-QACsの活性より高くなった．M-bis-QACsの活性は，アンモニウム窒素の電子密度に影響を受けるが，Ph-bis-QACsはそれに依存しないことが分かった．従って，bis-QACの抗菌活性は，アンモニウム窒素の電子密度よりもスペーサ鎖の回転軸を減少させること，分子構造の剛直性を上昇させることによって，より強化されると考えられ，bis-QACの立体構造が，bis-QACの抗菌活性の重要な因子であると示唆した．


銀担持アクリル繊維を含む抗菌紙の殺菌作用機構

銀担持アクリル繊維を含む抗菌紙の殺菌作用機構

銀担持アクリル繊維とポリエステル繊維から作製したiziの抗菌特性と殺菌作用機構を検討した．iziは，病原性細菌，Legionella pneumophila Sg1 IID 5232などを含む13菌株に対して広く高い抗菌スペクトルを示した．iziの殺菌力は，食塩，ペプトン共存下で低下することを認めた．iziの殺菌化学種は，電子スピン共鳴スペクトルと，スーパーオキシドジスムターゼもしくはヨウ化カリウムのようなラジカルスカベンジャーにより活性阻害が起こることから，ヒドロキシラジカルであることを証明し，細菌細胞中で変換されたリビングラジカルが，継続的な殺菌効果を示すことを示唆した．また，細菌細胞が，iziから銀イオンを引き抜くことを示唆した．

Journal of Antibacterial and Antifungal Agents, Japan


Synthesis and antimicrobial characteristics of 4,4',4''-(1,2,3-propylene trithio)tris(1-alkylpyridinium iodide)s

トリス型四級アンモニウム化合物 (tris-QAC) 4,4',4''-(1,2,3-propylene-trithio)tris (1-alkylpyridinium iodide)s (4TP-n: アルキル基の炭素数 n = 4,6,8,10,12,14)を合成し，抗菌特性を検討した．4TP-nは，3つのN-alkyl-4-thiopyridinium iodideをプロパンの1,2,3位で結合したトリス型構造を有する．4TP-nの抗菌特性を，ビス型四級アンモニウム化合物 (bis-QAC) 4,4'-(1,6-hexamethylenedithio)bis(1-alkylpyridinium iodide)s (4DTBP-6,n)，モノ型四級アンモニウム化合物 (mono-QAC) N-alkylpyridinium iodide (P-n)，そして商業的な抗菌剤，防黴剤と比較した．4TP-nの静菌，殺菌活性は，4DTBP-6,nと同様に高く，またアルキル鎖長の影響をほとんど受けなかった．4TP-nは，広くかつ強い抗菌スペクトルを有していた．4TP-nの殺菌活性は，pH，温度の影響を受け，その影響を全く受けない4DTBP-6,8とは異なっていた．


Control of Legionella species and host amoeba by bis-quaternary ammonium compounds

レジオネラ属菌(Legionella species)はレジオネラ症の原因菌であり，アメーバ類に寄生し増殖することが知られている．レジオネラ属菌の制御を行うためには，宿主アメーバに対しても高い活性を有する殺菌剤が必要である．そこで，一般的な薬剤と比較して広くかつ強い抗菌スペクトルを示し低毒性のビス型第四アンモニウム化合物(bis-QAC)，4,4'-(1,6-hexamethylenedithio)bis(1-octylpyridimium iodide) (4DTBP-6,8) および N,N'-hexamethylenebis(4-carbamoyl-1-decylpyridinium bromide) (D-38)の適用を検討した．これらのbis-QACは，レジオネラ属菌(L. pneumophila 2種とL. bozemanii 1種)に対して従来の薬剤よりも高い殺菌効果を示しただけでなく，Acanthamoebaの栄養型とそのシストに対しても非常に強い効果を示す殺菌剤であった．


Effects of light irradiation on deoxynivalenol production and TRI genes expression in Fusarium sp.

次世代光フォーラム2024 in 徳島 論文集

次世代光フォーラム2024 in 徳島 論文集


フェルラ酸とUV-Aの併用殺菌力における酸素の影響

フェルラ酸とUV-Aの併用殺菌力における酸素の影響

LED総合フォーラム 2022 in 徳島 論文集

LED総合フォーラム 2022 in 徳島 論文集


フェノール酸とブルーライトを併用した真菌の光不活性化

フェノール酸とブルーライトを併用した真菌の光不活性化

LED総合フォーラム 2021 in 徳島 論文集

LED総合フォーラム 2021 in 徳島 論文集


深紫外線および青色LEDによる釜揚げしらすの光殺菌

深紫外線および青色LEDによる釜揚げしらすの光殺菌

LED総合フォーラム 2021 in 徳島 論文集

LED総合フォーラム 2021 in 徳島 論文集


次世代光による細胞光応答の解明

次世代光による細胞光応答の解明

LED総合フォーラム 2020 in 徳島 論文集

LED総合フォーラム 2020 in 徳島 論文集


紫外線および青色LEDによる釜揚げしらすの細菌の不活化

紫外線および青色LEDによる釜揚げしらすの細菌の不活化

LED総合フォーラム 2020 in 徳島 論文集

LED総合フォーラム 2020 in 徳島 論文集


フェルラ酸と紫外線-Aの酵母に対する併用殺菌機構の解析

フェルラ酸と紫外線-Aの酵母に対する併用殺菌機構の解析

LED総合フォーラム 2019 in 徳島 論文集

LED総合フォーラム 2019 in 徳島 論文集


紫外線および青色LEDによる釜揚げしらすの微生物制御

紫外線および青色LEDによる釜揚げしらすの微生物制御

LED総合フォーラム 2019 in 徳島 論文集

LED総合フォーラム 2019 in 徳島 論文集


フェルラ酸と紫外線-Aの酵母に対する併用殺菌機構とそのポストハーベスト保存法としての検討

LED総合フォーラム 2018 in 徳島 論文集

LED総合フォーラム 2018 in 徳島 論文集


フェルラ酸と紫外線-Aの併用殺菌機構

フェルラ酸と紫外線-Aの併用殺菌機構

LED総合フォーラム 2018 in 徳島 論文集

LED総合フォーラム 2018 in 徳島 論文集


Bactericidal action of UV-A light-irradiated ferulic acid

4th World Congress and Expo on Applied Microbiology J. Microb. Biochem. Technol.


フェルラ酸と紫外線(UV-A)の併用による食品媒介病原性微生物および食品腐敗微生物の不活化

LED総合フォーラム 2016 in 徳島 論文集

LED総合フォーラム 2016 in 徳島 論文集


フェルラ酸とその誘導体を用いた近紫外光殺菌とその殺菌機構

フェルラ酸とその誘導体を用いた近紫外光殺菌とその殺菌機構

LED総合フォーラム 2015 in 徳島 論文集

LED総合フォーラム 2015 in 徳島 論文集


フォトクロミック分子を応用した光応答型殺菌剤の開発

フォトクロミック分子を応用した光応答型殺菌剤の開発


ジェミニ型抗菌剤ハイジェニアとLED近紫外光の併用による相乗殺菌効果とその殺菌機構の解明

LED総合フォーラム2013 in 徳島 論文集

LED総合フォーラム2013 in 徳島 論文集


ジェミニ型抗菌剤とUVA-LED照射による殺菌相乗効果とその殺菌機構

ジェミニ型抗菌剤とUVA-LED照射による殺菌相乗効果とその殺菌機構

LED総合フォーラム2012 in 徳島 論文集

LED総合フォーラム2012 in 徳島 論文集


MexT-mediated Regulation of MexEF-OprN Multidrug Efflux Pump via Nod Box in Pseudomonas aeruginosa


ジェミニ型抗菌剤とUVA-LED照射による殺菌相乗効果とその殺菌機構

ジェミニ型抗菌剤とUVA-LED照射による殺菌相乗効果とその殺菌機構

LED総合フォーラム2011 in 徳島 論文集

LED総合フォーラム2011 in 徳島 論文集


ジェミニ型抗菌剤とUVA-LED照射による殺菌相乗効果

ジェミニ型抗菌剤とUVA-LED照射による殺菌相乗効果

LED総合フォーラム論文集

LED総合フォーラム論文集


Novel antimicrobial agents, immobilized 1-alkyl-1'-(ω-hydroxypolymethylene)-4,4'-dipyridinium dibromides on inorganic materials

論文題目:新規無機担体に固定化した1-Alkyl-1'-(ω-ヒドロキシポリメチレン)-4,4'-ジピリジニウムジブロマイド抗菌剤，新規第四アンモニウム塩1-アルキル-1'-(ω-ヒドロキシポリメチレン)-4,4'-ジピリジニウムジブロマイドの合成方法を確立し，抗菌特性を調べた．その結果，抗菌活性に及ぼすアルキル鎖長の影響は小さく，1-アルキル-4,4'-ピリジルピリジニウムブロマイド，1-アルキルピリジニウムアイオダイド，塩化ベンザルコニウム，チアベンダゾールと比較して広い抗菌スペクトルと高い抗菌·抗黴活性を有し，抗菌活性はpHや温度の影響を受けにくいことが判明した．さらにガラスビーズに固定化し抗菌活性を確認した．

Proceedings of the 2nd International Conference on Advanced Materials Development and Performance Evaluation and Application