Biological effects of inhaled crude oil vapor. III. Pulmonary inflammation, cytotoxicity, and gene expression profile.

OBJECTIVE: Workers may be exposed to vapors emitted from crude oil in upstream operations in the oil and gas industry. Although the toxicity of crude oil constituents has been studied, there are very few in vivo investigations designed to mimic crude oil vapor (COV) exposures that occur in these operations. The goal of the current investigation was to examine lung injury, inflammation, oxidant generation, and effects on the lung global gene expression profile following a whole-body acute or sub-chronic inhalation exposure to COV. MATERIALS AND METHODS: To conduct this investigation, rats were subjected to either a whole-body acute (6 hr) or a sub-chronic (28 d) inhalation exposure (6 hr/d × 4 d/wk × 4 wk) to COV (300 ppm; Macondo well surrogate oil). Control rats were exposed to filtered air. One and 28 d after acute exposure, and 1, 28, and 90 d following sub-chronic exposure, bronchoalveolar lavage was performed on the left lung to collect cells and fluid for analyses, the apical right lobe was preserved for histopathology, and the right cardiac and diaphragmatic lobes were processed for gene expression analyses. RESULTS: No exposure-related changes were identified in histopathology, cytotoxicity, or lavage cell profiles. Changes in lavage fluid cytokines indicative of inflammation, immune function, and endothelial function after sub-chronic exposure were limited and varied over time. Minimal gene expression changes were detected only at the 28 d post-exposure time interval in both the exposure groups. CONCLUSION: Taken together, the results from this exposure paradigm, including concentration, duration, and exposure chamber parameters, did not indicate significant and toxicologically relevant changes in markers of injury, oxidant generation, inflammation, and gene expression profile in the lung.

Biological effects of crude oil vapor. IV. Cardiovascular effects.

Workers in the oil and gas extraction industry are at risk of inhaling volatile organic compounds. Epidemiological studies suggest oil vapor inhalation may affect cardiovascular health. Thus, in this hazard identification study we investigated the effects of inhalation of crude oil vapor (COV) on cardiovascular function. Male rats were exposed to air or COV (300 ppm) for 6 h (acute), or 6 h/day × 4 d/wk. × 4 wk. (sub-chronic). The effects of COV inhalation were assessed 1, 28, and 90 d post-exposure. Acute exposure to COV resulted in reductions in mean arterial and diastolic blood pressures 1 and 28 d after exposure, changes in nitrate-nitrite and H2O2 levels, and in the expression of transcripts and proteins that regulate inflammation, vascular remodeling, and the synthesis of nitric oxide (NO) in the heart and kidneys. The sub-chronic exposure resulted in a reduced sensitivity to α1-adrenoreceptor-mediated vasoconstriction in vitro 28 d post-exposure, and a reduction in oxidative stress in the heart. Sub-chronic COV exposure led to alterations in the expression of NO synthases and anti-oxidant enzymes, which regulate inflammation and oxidative stress in the heart and kidneys. There seems to be a balance between changes in the expression of transcripts associated with the generation of reactive oxygen species (ROS) and antioxidant enzymes. The ability of antioxidant enzymes to reduce or inhibit the effects of ROS may allow the cardiovascular system to adapt to acute COV exposures. However, sub-chronic exposures may result in longer-lasting negative health consequences on the cardiovascular system.

The Effect of Ethanol Treatment on the Quality of a New Table Grape Cultivar It 681-30 Stored at Low Temperature and after a 7-Day Shelf-Life Period at 20 °C: A Molecular Approach.

Despite the fact that many studies have examined the effectiveness of different gaseous postharvest treatments applied at low temperature to maintain table grape quality, the use of ethanol vapor has hardly been investigated. Thus, this work has studied the effectiveness of ethanol vapor-generating sachets in the maintenance of It 681-30 table grape quality, a new cultivar, during storage at low temperature and after the shelf-life period at 20 °C. To this end, various quality assessments have been carried out and the effect of the ethanol treatment on the expression of different genes (phenylpropanoids, transcription factors, PRs, and aquaporins) was determined. The results indicated that the application of ethanol vapor reduced the total decay incidence, weight loss, and the rachis browning index in It 681-30 grapes stored at 0 °C and after the shelf-life period at 20 °C, as compared to non-treated samples. Moreover, the modulation of STS7 and the different PR genes analyzed seems to play a part in the molecular mechanisms activated to cope with fungal attacks during the postharvest of It 681-30 grapes, and particularly during the shelf-life period at 20 °C. Furthermore, the expression of aquaporin transcripts was activated in samples showing higher weight loss. Although further work is needed to elucidate the role of ethanol in table grape quality, the results obtained in this work provide new insight into the transcriptional regulation triggered by ethanol treatment.

Disruption of thin- and thick-wall microalgae using high pressure gases: Effects of gas species, pressure and treatment duration on the extraction of proteins and carotenoids.

Industrial scale microalgal cell disruption requires low cost, high efficiency and structural conservation of biomolecules for biorefinery. Many cultivated microalgae have thick walls and these walls are barriers for efficient cell disruption. Until recently, despite the high biodiversity of microalgae, little attention has been paid to thin-wall microalgal species in the natural environment for the production and recovery of valuable biomolecules. Instead of developing high power cell disruption devices, utilization of thin-wall species would be a better approach. The present paper describes a simple device that was assembled to evaluate the viability and effectiveness of biomolecule extraction from both thin- and thick-wall species as a proof of concept. This device was tested with high-pressure gases including N2, CO2 plus N2, and air as the disruption force. The highest nitrogen pressure, 110 bar, was not able to disrupt the thick-wall microalgal cells. On the other hand, the thin-wall species was disrupted to different degrees using different pressures and treatment durations. In the same treatment duration, higher nitrogen pressure gave better cell disruption efficiency than the lower pressure. However, in the same pressure, longer treatment duration did not give better efficiency than the shorter duration. High pressure CO2 treatments resulted in low soluble protein levels in the media. The best conditions to disrupt the thin-wall microalgal cells were 110 bar N2 or air for 1 min among these tests. In these conditions, not only were the disruption efficiencies high, but also the biomolecules were well preserved.

Synergistic activities of gaseous oregano and thyme thymol essential oils against Listeria monocytogenes on surfaces of a laboratory medium and radish sprouts.

We investigated combinations of gaseous essential oils (EO gases) for their synergistic inhibitory activities against Listeria monocytogenes on a laboratory medium and radish sprouts. The minimum inhibitory concentrations and minimum lethal concentrations of oregano, thyme thymol, and cinnamon bark EO gases against L. monocytogenes were 0.0781 µL/mL on nutrient agar supplemented with glucose and bromocresol purple (NGBA). A checkerboard assay showed that combinations of oregano and thyme thymol EO gases and of oregano and cinnamon bark EO gases exert the strongest synergistic antilisterial activity (fractional inhibitory concentration index [FICI] = 0.3750). A combination of thyme thymol and cinnamon bark EO gases also had a synergistic effect (FICI = 0.5000) on L. monocytogenes on NGBA. Combinations of oregano and thyme thymol EO gases were tested for synergistic antimicrobial activity against L. monocytogenes on radish sprouts. A combination of these gases, each at 0.313 µL/mL, caused a significant (P ≤ 0.05) reduction in the number of L. monocytogenes on radish sprouts compared with reductions caused by treatment with oregano or thyme thymol EO gas alone at the same concentration. Our findings provide information that will be useful when developing antimicrobial applications using EO gases to control L. monocytogenes in the food industry.

Evaluation of Steady-State Gaseous Chlorine Dioxide Treatment for the Inactivation of Tulane virus on Berry Fruits.

The effectiveness of steady-state levels of gaseous chlorine dioxide (ClO2) against Tulane virus (TV), a human norovirus surrogate, on berries was determined. The generated ClO2 was maintained at 1 mg/L inside a 269 L glove box to treat two 50 g batches of blueberries, raspberries, and blackberries, and two 100 g batches of strawberries that were immersion coated with TV. The standardized/normalized treatment concentrations of ClO2 ranging from 0.63 to 4.40 ppm-h/g berry were evaluated. When compared to untreated TV contaminated berries, log reductions of TV were in excess of 2.9 log PFU/g for all berry types and conditions tested, indicating that ClO2 was highly effective. In general, the efficacy of all ClO2 treatments on log reductions of TV on all berries was not significantly different (p < 0.05). The average log reduction with strawberries, raspberries, blueberries, and blackberries, treated with the lowest ClO2 concentration, 0.63 ppm-h/g, were 2.98, 3.40, 3.82, and 4.17 log PFU/g, respectively. Overall results suggest that constant levels of ClO2 could be quite effective against foodborne viruses.

Plug-and-Play Continuous Gas Flow Assembly of Cysteine-Inserted AuCu Nanobimetals for Folate-Receptor-Targeted Chemo-Phototherapy.

Conjugatable nanobimetals exhibiting broadband light absorption for use as phototherapeutic platforms were assembled via a plug-and-play continuous gas flow route. Electrically produced AuCu nanobunches (NBs) under nitrogen gas flow were directly injected into cysteine (cys) solution through gas pressurization to mechanically spray the solution (AuCu into cys droplets). The sprayed droplets were then exposed to 185 nm UV light (higher photon energy [6.2 eV] than the work functions of Au [5.1 eV] and Cu [4.7 eV]) to initiate photoionization of AuCu NBs for subsequent electrostatic reaction with the SH- group of cys to form cys-inserted AuCu (AuCu-cys) platforms in a single-pass gas stream. These platforms exhibited broadband light absorption spectra because of hybridized interparticle plasmonic coupling and could be conjugated to folic acid (FA) when dispersed in FA solution to form highly dispersible, biocompatible, and cancer-targetable AuCu-cys-FA. This material was suitable for use in targeted phototherapy of folate-receptor (FR)-rich cancers via FR-mediated endocytosis, and loading doxorubicin (DOX) into AuCu-cys-FA (i.e., AuCu-cys-DOXFA) facilitated chemo-phototherapy because of photoresponsive anticancer drug release upon induction of hyperthermia.

Inactivation of Salmonella Typhimurium on red chili peppers by treatment with gaseous chlorine dioxide followed by drying.

Chili pepper (Capsicum annuum L.) powder and other powdered spices containing chili peppers are occasionally contaminated with foodborne pathogens. We applied chlorine dioxide (ClO2) gas treatment to chili peppers prior to drying to inactivate Salmonella Typhimurium. Chili peppers inoculated with S. Typhimurium were exposed to ClO2 gas generated from 0.77 mL of aqueous ClO2 for 6 h at 25 °C and 100% relative humidity, followed by air drying at 55 °C for up to 24 h. Populations of S. Typhimurium and total aerobic bacteria (TAB) on peppers, chromaticity values, and moisture content were determined after various treatment times. S. Typhimurium (ca. 5.6 log cfu/g) was reduced to <0.7 log cfu/g of peppers treated with ClO2 gas for 0.5 h at 25 °C, but was detected by enrichment (>1 cfu/10.8 g) after treatment for 4 h. The pathogen was not detected after treatment with ClO2 gas for 6 h. S. Typhimurium did not decrease significantly (P > 0.05) on peppers exposed to air at 25 °C for 6 h, but rapidly decreased to 1.6 log cfu/g after subsequent drying for 6 h at 55 °C. The initial number of TAB (ca. 6.5 log cfu/g) decreased to 1.4 log cfu/g after treatment with ClO2 gas for 0.5 h and was less than the detection limit (0.7 log cfu/g) after 2 h. TAB counts were not reduced by treating peppers with air for 6 h, but decreased to <0.7 log cfu/g after subsequent drying for 24 h at 55 °C. The lightness (L value) of treated and untreated chili peppers did not change during drying, but redness (a value) and yellowness (b value) decreased. Results showed that treatment of chili peppers containing S. Typhimurium (5.6 log cfu/g) with ClO2 gas for 6 h prior to drying at 55 °C reduced the population to < 1 cfu/10.8 g.

Antimicrobial activities of gaseous essential oils against Listeria monocytogenes on a laboratory medium and radish sprouts.

The aim of this study was to evaluate the antimicrobial activities of gaseous essential oils (EO gases) against Listeria monocytogenes on the surfaces of a laboratory medium and radish sprouts. We determined the minimal inhibitory concentration (MIC) and minimal lethal concentration (MLC) values of EO gases from eight EOs extracted from basil leaves, carrot seed, cinnamon bark, cinnamon leaves, clove flower buds, oregano leaves, thyme flowers (linalool), and thyme leaves (thymol) against L. monocytogenes on a nutrient agar supplemented with 1% glucose and 0.025% bromocresol purple (NGBA). Oregano, thyme thymol, and cinnamon bark EO gases showed the strongest antilisterial activities (MIC and MLC, 78.1µL/L). We also investigated the inhibitory and lethal activities of these gases against L. monocytogenes on the surface of radish sprouts. The number of L. monocytogenes after exposure to EO gases at ≥156µL/L was significantly (P≤0.05) lower than that of untreated L. monocytogenes. For example, the initial number of L. monocytogenes on the surface of radish sprouts (ca. 6.3logCFU/g) decreased by 1.4logCFU/g within 24h at 30°C and 43% relative humidity (RH) without EO gas treatment, whereas the number of L. monocytogenes after exposure to oregano, thyme thymol, and cinnamon bark EO gases at 156µL/L decreased by 2.1, 2.1, and 1.8logCFU/g, respectively, after 24h. Although EO gases exerted greater lethal activities at higher concentrations (312 and 625µL/L), L. monocytogenes on the surface of radish sprouts was not completely inactivated. The number of L. monocytogenes on sprouts treated with oregano, thyme thymol, and cinnamon bark EO gases at 625µL/L decreased by 2.7-3.0logCFU/g after 24h at 30°C and 43% RH. Results indicate that EO gases that showed antilisterial activities on a laboratory medium also exhibited reduced lethal activity on the surface of radish sprouts. These findings will be useful when developing strategies to inactivate L. monocytogenes and possibly other foodborne pathogens on sprouts and perhaps other foods using EO gases.

A gaseous acetic acid treatment to disinfect fenugreek seeds and black pepper inoculated with pathogenic and spoilage bacteria.

Contamination of spices by pathogenic and/or spoilage bacteria can be deleterious to consumer's health and cause deterioration of foods, and inactivation of such bacteria is necessary for the food industry. The present study examined the effect of gaseous acetic acid treatment in reducing Escherichia coli O157:H7, Salmonella Enteritidis and Bacillus subtilis populations inoculated on fenugreek seeds and black pepper. Treatment with gaseous acetic acid at 0.3 mmol/L, 0.6 mmol/L and 4.7 mmol/L for 1-3 h significantly reduced the populations of E. coli O157:H7 and Salmonella Enteritidis on black pepper and fenugreek seeds at 55 °C (p < 0.05). The gas treatments at 4.7 mmol/L were more effective in inactivating the pathogens than the treatment at 0.3 mmol/L. An approximately 5.0 log reduction was obtained after 3 h of treatment with 4.7 mmol/L acetic acid. No significant reductions in the population of B. subtilis spores inoculated on fenugreek seeds and black pepper were obtained after the gas treatments at 0.3 mmol/L or 0.6 mmol/L (p > 0.05). However, the gas treatment at 4.7 mmol/L significantly reduced B. subtilis spores (p < 0.05), and 4.0 log CFU/g and 3.5 log CFU/g reductions on fenugreek seeds and black pepper, respectively, were obtained after 3 h of treatment.

Microalgal biomass and lipid production in mixed municipal, dairy, pulp and paper wastewater together with added flue gases.

The aim of the study was to grow microalgae on mixed municipal and industrial wastewater to simultaneously treat the wastewater and produce biomass and lipids. All algal strains grew in all wastewater mixtures; however, Selenastrum minutum had the highest biomass and lipids yields, up to 37% of the dry matter. Nitrogen and phosphorus removal were high and followed a similar trend in all three strains. Ammonium was reduced from 96% to 99%; this reduction was due to algal growth and not to stripping to the atmosphere, as confirmed by the amount of nitrogen in the dry algal biomass. Phosphate was reduced from 91% to 99%. In all strains used the lipid content was negatively correlated to the nitrogen concentration in the algal biomass. Mixtures of pulp and paper wastewater with municipal and dairy wastewater have great potential to grow algae for biomass and lipid production together with effective wastewater treatment.

Combined remediation and lipid production using Chlorella sorokiniana grown on wastewater and exhaust gases.

Substitution of conventional feedstock with waste based alternatives is one route towards both remediation and reducing costs associated with production of algal biomass. This work explores whether exhaust gases and wastewater can replace conventional feedstock in the production of biomass from Chlorella sorokiniana. Exhaust gases were used to augment production in final effluent, anaerobic digester centrate or in standard medium. Cultures were grown in 1L bottles under illumination of 80 µmol m(-2) s(-1). The results showed an average µmax ranging between 0.04 and 0.07 h(-1), whilst the final biomass yield in different media ranged between 220 and 330 mg L(-1). Lipid yield was increased over time to 31 mg L(-1). CO2 addition resulted in complete nitrogen removal between 48 and 96 h in both final effluent and centrate. The results also indicated that levels of carbon monoxide, carbon dioxide and nitrogen oxides in the exhaust gases can be reduced by between 20% and 95%.

Inactivation of Salmonella enterica serovar Typhimurium on fresh produce by cold atmospheric gas plasma technology.

Cold atmospheric gas plasma treatment (CAP) is an alternative approach for the decontamination of fresh and minimally processed food. In this study, the effects of growth phase, growth temperature and chemical treatment regime on the inactivation of Salmonella enterica serovar Typhimurium (S. Typhimurium) by Nitrogen CAP were examined. Furthermore, the efficacy of CAP treatment for decontaminating lettuce and strawberry surfaces and potato tissue inoculated with S. Typhimurium was evaluated. It was found that the rate of inactivation of S. Typhimurium was independent of the growth phase, growth temperature and chemical treatment regime. Under optimal conditions, a 2 min treatment resulted in a 2.71 log-reduction of S. Typhimurium viability on membrane filters whereas a 15 min treatment was necessary to achieve 2.72, 1.76 and 0.94 log-reductions of viability on lettuce, strawberry and potato, respectively. We suggest that the differing efficiency of CAP treatment on the inactivation of S. Typhimurium on these different types of fresh foods is a consequence of their surface features. Scanning electron microscopy of the surface structures of contaminated samples of lettuce, strawberry and potato revealed topographical features whereby S. Typhimurium cells could be protected from the active species generated by plasma.

Development and testing of hyperbaric atomic force microscopy (AFM) and fluorescence microscopy for biological applications.

A commercially available atomic force microscopy and fluorescence microscope were installed and tested inside a custom-designed hyperbaric chamber to provide the capability to study the effects of hyperbaric gases on biological preparations, including cellular mechanism of oxidative stress. In this report, we list details of installing and testing atomic force microscopy and fluorescence microscopy inside a hyperbaric chamber. The pressure vessel was designed to accommodate a variety of imaging equipment and ensures full functionality at ambient and hyperbaric conditions (≤85 psi). Electrical, gas and fluid lines were installed to enable remote operation of instrumentation under hyperbaric conditions, and to maintain viable biological samples with gas-equilibrated superfusate and/or drugs. Systems were installed for vibration isolation and temperature regulation to maintain atomic force microscopy performance during compression and decompression. Results of atomic force microscopy testing demonstrate sub-nanometre resolution at hyperbaric pressure in dry scans and fluid scans, in both contact mode and tapping mode. Noise levels were less when measurements were taken under hyperbaric pressure with air, helium (He) and nitrogen (N(2) ). Atomic force microscopy and fluorescence microscopy measurements were made on a variety of living cell cultures exposed to hyperbaric gases (He, N(2) , O(2) , air). In summary, atomic force microscopy and fluorescence microscopy were installed and tested for use at hyperbaric pressures and enables the study of cellular and molecular effects of hyperbaric gases and pressure per se in biological preparations.

Antitumor effects of nano-bubble hydrogen-dissolved water are enhanced by coexistent platinum colloid and the combined hyperthermia with apoptosis-like cell death.

In order to erase reactive oxygen species (ROS) related with the proliferation of tumor cells by reducing activity of hydrogen, we developed functional water containing nano-bubbles (diameters: <900 nm for 71%/population) hydrogen of 1.1-1.5 ppm (the theoretical maximum: 1.6 ppm) with a reducing ability (an oxidation-reduction potential -650 mV, normal water: +100-200 mV) using a microporous-filter hydrogen-jetting device. We showed that hydrogen water erased ROS indispensable for tumor cell growth by ESR/spin trap, the redox indicator CDCFH-DA assay, and was cytotoxic to Ehrlich ascites tumor cells as assessed by WST-8 assay, crystal violet dye stain and scanning electron microscopy, after 24-h or 48-h incubation sequent to warming at 37°C or 42°C. Hydrogen water supplemented with platinum colloid (0.3 ppm Pt in 4% polyvinylpyrrolidone) had more antitumor activity than hydrogen water alone, mineral water alone (15.6%), hydrogen water plus mineral water, or platinum colloid alone as observed by decreased cell numbers, cell shrinkage and pycnosis (nuclear condensation)/karyorrhexis (nuclear fragmentation) indicative of apoptosis, together with cell deformation and disappearance of microvilli on the membrane surface. These antitumor effects were promoted by combination with hyperthermia at 42°C. Thus, the nano-bubble hydrogen water with platinum colloid is potent as an anti-tumor agent.

Effect of oxygen concentration in gas phase on sporulation and individual ganoderic acids accumulation in liquid static culture of Ganoderma lucidum.

Effects of oxygen concentration within 21-100% in gaseous phase on the morphology and ganoderic acids (GAs) production by Ganoderma lucidum in liquid static culture were studied. A higher oxygen concentration increased individual GAs production, and more spores and higher total GA content were obtained at an oxygen level of 80%.

A simple instrument-free gaseous chlorine dioxide method for microbial decontamination of potatoes during storage.

An instrument-free gaseous chlorine dioxide (ClO(2)) method to control microorganisms on potatoes during storage was developed. Gaseous ClO(2) was generated by combining an equal amount of impregnated sodium chlorite and activating acids in a sachet without using any solution or equipment. After activation by mixing, the sachet was placed in the application area. The decontamination efficiency of ClO(2) on natural microbiota including total microorganisms, yeasts and molds, and inoculated Pseudomonas aeruginosa on potatoes was investigated. Different treatments using 2, 3, and 4 g of materials and various time intervals (2.5 and 5 h) to generate 16, 20, 24, 30, 32, and 40 mg/L of ClO(2) were evaluated. The results were effective for natural microbiota, showing over a 5 log CFU/potato reduction with a 4 g treatment after 5 h. For P. aeruginosa, there was almost a 6 log CFU/potato reduction after 5 h of the 4 g treatment. The lowest treatment tested (2 g at 2.5 h) showed reductions of 1.7, 1.9, and 2.3 log CFU/potato for total microorganisms, yeasts and molds, and P. aeruginosa, respectively. Gaseous ClO(2) did not affect the overall visual quality of the potato. The residue of ClO(2) decreased to <1 mg/L after 14 days for each treatment, indicating ClO(2) dissipates naturally over time.

Effects of essential oil treatment, gas atmosphere, and storage temperature on Listeria monocytogenes in a model vegetable system.

Natural antimicrobials such as plant essential oils (EOs) may be useful for controlling pathogenic bacteria on fresh-cut vegetables. The antilisterial properties of EOs (thyme, oregano, and rosemary), in combination with different storage atmospheres (air, 5% CO2-2% O2-93% N2, and 20% CO2-1% O2-79% N2) and temperatures (4 and 80C), were examined using a gas flow-through system combined with a vegetable agar model. The antimicrobial effects of the EOs varied depending on the oil, the Listeria strain and species, the method of application, and the storage conditions tested. Using the disk diffusion assay, the antilisterial effectiveness of the oils was in the following order: thyme EO > oregano EO > rosemary EO. Volatiles released from the EOs resulted in very small antilisterial effects, indicating that the oils needed to be in direct contact with cultures in order to be effective. There were strain and species effects, with L. innocua NCTC 11288 exhibiting the strongest resistance to EOs, and L. monocytogenes NCTC 7973 being the most sensitive strain. In addition, the effectiveness of the EOs was influenced by storage atmosphere and temperature. Use of EOs in combination with a gas atmosphere of 20% CO2-1% O2-79% N2 had the greatest antilisterial effect, suggesting that high CO2 atmospheres enhanced the antilisterial properties of EOs. Lowering the storage temperature from 8 to 4OC improved the antilisterial activity of thyme oil. It is concluded that thyme and oregano EOs display strong inhibitory effects against Listeria and that increasing CO2 levels and lowering storage temperatures further enhance these antilisterial effects.

Determination of Legionella pneumophila susceptibility to Melaleuca alternifolia Cheel (tea tree) oil by an improved broth micro-dilution method under vapour controlled conditions.

The aim of this study was to determine the in vitro activity of Melaleuca alternifolia Cheel (tea tree) oil (TTO) against 22 strains of Legionella pneumophila of different serogroup and source of isolation. Both a standard broth micro-dilution method, with slight modifications, and a micro-atmosphere diffusion method were used. Furthermore, we have established a simple sealing procedure in the micro-dilution method to determine the antibacterial activity of TTO against Legionella in aqueous phase. The results showed that L. pneumophila, quite irrespective of serogroup and source of isolation, is exquisitely sensitive to TTO, with minimal inhibitory concentration (MIC) ranging from 0.125 to 0.5% v/v, and a bactericidal activity at 0.5% v/v. In addition, we show here that TTO vapours exert critical activity, that must be controlled for reproducible MIC determinations. Overall, our data suggest that TTO could be active as anti-Legionella disinfectant, for control of water system contamination, especially in spas, in small waterlines or in particular respiratory medical devices.

Effects of a novel gaseous antioxidative system containing a rosemary extract on the oxidation induced by nitrogen dioxide and ultraviolet radiation.

Rosemary is commonly used as a spice and a flavoring agent in food processing. Although the antioxidative properties of its extracts have been investigated, there have been few reports on the volatile components of rosemary. We designed a novel antioxidative system which can generate the volatile constituents in the gaseous phase from a rosemary extract and evaluated the gaseous antioxidative activities against both lipid peroxidation and cell death induced by nitrogen dioxide and ultraviolet radiation. The antioxidative effects of the major volatile components on the oxidation of linoleic acid induced by azo compounds were also investigated in a solution. The volatile components in the novel antioxidative system suppressed the Jurkat cell death induced by nitrogen dioxide and the intracellular formation of reactive oxygen species in fibroblast cells induced by ultraviolet radiation. 1,8-Cineole among the volatile components exerted an antioxidative effect against the oxidation of linoleic acid in a solution induced by azo compounds and ultraviolet radiation. These data suggest that the volatile constituents of a rosemary extract had antioxidative properties and that gaseous exposure antioxidant is a promising method for promoting health.