ABSTRACT
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.
Subject(s)
Petroleum , Pneumonia , Rats , Animals , Petroleum/toxicity , Petroleum/metabolism , Transcriptome , Pneumonia/pathology , Lung , Gases/analysis , Gases/metabolism , Gases/pharmacology , Inflammation/pathology , Oxidants/metabolism , Bronchoalveolar Lavage Fluid , Inhalation Exposure/adverse effects , Inhalation Exposure/analysisABSTRACT
Biofilms are surface-associated microbial clusters embedded in extracellular polymeric substances. Biofilms formed on food-contact surfaces create challenges for the food industry due to their increased tolerance to antimicrobial agents and disinfectants. This study aimed to evaluate the effect of the biofilm maturation period on their resistance to gaseous ClO2. Listeria monocytogenes, Salmonellaserotype Typhimurium, and Escherichia coli O157:H7 biofilms formed on stainless steel (SS) and high-density polyethylene (HDPE) surfaces were investigated. The total cell mass and protein content significantly increased (P < .05) between the second and the fifth day of maturation, and the biofilms' resistance to gaseous ClO2 increased as they matured. Generally, the cell counts of 0-day-old L. monocytogenes, Salm. Typhimurium, and E. coli O157:H7 biofilms on SS and HDPE reduced below the detection limit (0.48 log CFU/cm2) within 5 min. The cell counts of 2-day-old biofilms of the three pathogens were reduced by 6.22 to over 7.52 log, while those of 5-day-old biofilms were reduced by 3.64 to over 6.34 log after 20 min of treatment with 30 ppmv of gaseous ClO2. Therefore, as resistance increases with biofilm maturation, daily gaseous ClO2 treatment would maximize the antimicrobial efficacy of the cleaning strategy against biofilms.
Subject(s)
Anti-Infective Agents , Escherichia coli O157 , Gases/pharmacology , Colony Count, Microbial , Polyethylene/pharmacology , Food Microbiology , Biofilms , Anti-Infective Agents/pharmacologyABSTRACT
Food preservation is a critical issue in ensuring food safety and quality. Growing concern around industrial pollution of food and demand for environmentally sustainable food has led to increased interest in developing effective and eco-friendly preservation techniques. Gaseous ClO2 has gained attention for its strong oxidizing properties, high efficacy in microorganism inactivation, and potential for preserving the attributes and nutritional quality of fresh food while avoiding the formation of toxic byproducts or unacceptable levels of residues. However, the widespread use of gaseous ClO2 in the food industry is limited by several challenges. These include large-scale generation, high cost and environmental considerations, a lack of understanding of its mechanism of action, and the need for mathematical models to predict inactivation kinetics. This review aims to provide an overview of the up-to-date research and application of gaseous ClO2 . It covers preparation methods, preservation mechanisms, and kinetic models that predict the sterilizing efficacy of gaseous ClO2 under different conditions. The impacts of gaseous ClO2 on the quality attributes of fresh produce and low-moisture foods, such as seeds, sprouts, and spices, are also summarized. Overall, gaseous ClO2 is a promising preservation approach, and future studies are needed to address the challenges in large-scale generation and environmental considerations and to develop standardized protocols and databases for safe and effective use in the food industry.
Subject(s)
Disinfectants , Gases , Gases/pharmacology , Colony Count, Microbial , Disinfectants/chemistry , Kinetics , Food Preservation/methods , SeedsABSTRACT
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.
Subject(s)
Cardiovascular System , Petroleum , Animals , Antioxidants/metabolism , Antioxidants/pharmacology , Cardiovascular System/metabolism , Gases/pharmacology , Hydrogen Peroxide/pharmacology , Inflammation , Inhalation Exposure/adverse effects , Male , Oxidative Stress , Rats , Reactive Oxygen Species/metabolismABSTRACT
Objective: Stainless steel welding creates fumes rich in carcinogenic metals such as chromium (Cr). Welding consumables devoid of Cr are being produced in an attempt to limit worker exposures to toxic and carcinogenic metals. The study objective was to characterize a copper-nickel (Cu-Ni) fume generated using gas metal arc welding (GMAW) and determine the pulmonary deposition and toxicity of the fume in mice exposed by inhalation. Materials and Methods: Male A/J mice (6-8 weeks of age) were exposed to air or Cu-Ni welding fumes for 2 (low deposition) or 4 (high deposition) hours/day for 10 days. Mice were sacrificed, and bronchoalveolar lavage (BAL), macrophage function, and histopathological analyses were performed at different timepoints post-exposure to evaluate resolution. Results and Discussion: Characterization of the fume indicated that most of the particles were between 0.1 and 1 µm in diameter, with a mass median aerodynamic diameter of 0.43 µm. Metal content of the fume was Cu (â¼76%) and Ni (â¼12%). Post-exposure, BAL macrophages had a reduced ability to phagocytose E. coli, and lung cytotoxicity was evident and significant (>12%-19% fold change). Loss of body weight was also significant at the early timepoints. Lung inflammation, the predominant finding identified by histopathology, was observed as a subacute response early that progressively resolved by 28 days with only macrophage aggregates remaining late (84 days). Conclusions: Overall, there was high acute lung toxicity with a resolution of the response in mice which suggests that the Cu-Ni fume may not be ideal for reducing toxic and inflammatory lung effects.
Subject(s)
Air Pollutants, Occupational , Welding , Air Pollutants, Occupational/analysis , Air Pollutants, Occupational/toxicity , Animals , Chromium , Copper/toxicity , Escherichia coli , Gases/analysis , Gases/pharmacology , Lung , Male , Metals , Mice , Nickel/toxicity , Welding/methodsABSTRACT
Despite the controversy, sodium bicarbonate is a commonly used medication in critically ill patients of all ages. There is a lack of data on the acute impact on hemodynamic parameters, biomarker indicators of cardiac output, and changes in vasoinotropic support after sodium bicarbonate therapy. In our retrospective study on children with biventricular circulation in pediatric cardiac intensive care unit receiving bicarbonate therapy: we analyzed its effects on arterial blood gases, heart rate, blood pressure (BP), central venous pressures (CVP), cerebral and renal near-infrared spectroscopy (NIRS), changes in vasoinotropic and ventilator changes before and after sodium bicarbonate administration. Thirty-one administrations of sodium bicarbonate in 23 patients with congenital heart disease without residual shunts were analyzed. The average age was 15.4 months, weight 7.7 kg, and the average bicarbonate dose was 1 meq/kg. There was an increase in arterial pH from 7.24 to 7.30 (p = 0.14) and bicarbonate changed from 18 to 20 mEq/L (p = 0.23). No clinically significant changes were found in the following parameters: heart rate (141 ± 20.1 to 136 ± 19), systolic BP (84 ± 17 to 86 ± 14 mmHg), diastolic BP (48 ± 12 to 49 ± 12 mmHg), cerebral NIRS (64 ± 12 to 65 ± 12), renal NIRS (80 ± 10 to 81 ± 7), CVP (9 ± 3 to 10 ± 4 mmHg), paCO2 (45 ± 26 to 42 ± 7 mmHg), paO2 (143 ± 78 to 127 ± 59 mmHg), serum lactate (2.2 ± 2.7 to 3.6 ± 3.8 mmol/L), and vasoinotropic score (7.5 ± 5.0 to 7.7 ± 4.7). Outside of a change in serum pH and bicarbonate levels no other significant changes were noted after sodium bicarbonate administration in children with congenital heart disease with fully septated, biventricular circulation. There was no improvement in systemic oxygen delivery.
Subject(s)
Heart Defects, Congenital , Sodium Bicarbonate , Humans , Child , Infant , Sodium Bicarbonate/therapeutic use , Sodium Bicarbonate/pharmacology , Bicarbonates/pharmacology , Bicarbonates/therapeutic use , Retrospective Studies , Heart Defects, Congenital/drug therapy , Hemodynamics , Oxygen , Lactates/pharmacology , Biomarkers , Gases/pharmacologyABSTRACT
Zinc- and copper-containing welding fumes can cause systemic inflammation after exposure in humans. Recent ex vivo studies have shown that the observed inflammation originates from exposed immune cells. In vitro studies identified the soluble fraction of metal particles as the main effectors. Isolated perfused mouse lungs (IPLs) were perfused and ventilated for 270 min. Lungs were instilled with saline solution (control), welding fume particle suspension (WFs) or the soluble fraction of the welding fumes (SF-WFs). Bronchoalveolar lavage fluid (BALF) and perfusate samples were analyzed for cytokine levels and lung tissue mRNA expression levels were analyzed via RT-PCR. All lungs instilled with WFs did not complete the experiments due to a fatal reduction in tidal volume. Accordingly, IL-6 and MPO levels were significantly higher in BALF of WF lungs compared to the control. IL-6 and MPO mRNA expression levels were also increased for WFs. Lungs instilled with SF-WFs only showed mild reactions in tidal volume, with BALF and mRNA expression levels not significantly differing from the control. Zinc- and copper-containing welding fume particles adversely affect IPLs when instilled, as evidenced by the fatal loss in tidal volume and increased cytokine expression and secretion. The effects are mainly caused by the particles, not by the soluble fraction.
Subject(s)
Air Pollutants, Occupational , Welding , Air Pollutants, Occupational/toxicity , Animals , Copper/pharmacology , Cytokines/metabolism , Gases/pharmacology , Inflammation/etiology , Inhalation Exposure , Interleukin-6/genetics , Interleukin-6/pharmacology , Lung/metabolism , Mice , RNA, Messenger/genetics , Zinc/pharmacologyABSTRACT
AIM: To study the impact of incorporating micro-nano-bubbles (MNBs) in commonly used food antimicrobials (AMs) against Escherichia coli O157:H7 (EC) and Listeria monocytogenes (LM). METHODS AND RESULTS: Air, carbon dioxide (CO2 ) and nitrogen (N2 ) were used to incorporate MNBs in city water. AM solution (with or without MNBs) of 9 ml was individually taken into sterile test tubes and mixed with 1 ml of inoculum grown in brain heart infusion (BHI) broth to get the net AM concentrations of 28·4 ppm peracetic acid (PAA), 200 ppm chlorine (Cl2 ), 5·4% citric acid (CA) and 4·5% lactic acid (LA). After treatment time of 1·5 and 3·0 min, 1 ml of sample was neutralized using Dey-Engley neutralizing broth and plated on BHI agar. For EC, Cl2 -CO2 solutions resulted in significantly greater log reductions (5·2 logs) compared to that of Cl2 solutions without MNBs (3·8 logs). For LM, PAA-CO2 solutions resulted in significantly greater log reductions (4·4 logs) compared to that of PAA solutions without MNBs (1·7 logs). CONCLUSIONS: This study demonstrated that the efficacy of Cl2 and PAA AM solutions could be increased by incorporating CO2 -MNBs against EC and LM in microbiological growth medium. SIGNIFICANCE AND IMPACT OF THE STUDY: Incorporation of CO2 -MNBs in AM solutions could increase the efficacy of AMs against pathogens on/in food matrices, which should be tested in future research.
Subject(s)
Anti-Infective Agents/pharmacology , Food Microbiology/methods , Gases/pharmacology , Pasteurization/methods , Anti-Infective Agents/analysis , Colony Count, Microbial , Escherichia coli O157/drug effects , Escherichia coli O157/growth & development , Food Industry , Gases/analysis , Listeria monocytogenes/drug effects , Listeria monocytogenes/growth & developmentABSTRACT
Nuts, including almonds, are occasionally contaminated with Salmonella spp. In this study, we used chlorine dioxide (ClO2) gas to inactivate S. enterica subsp. Enterica serovar Enteritidis on almonds. Almonds inoculated with a single strain of S. Enteritidis (8.95 log cfu/mL) were exposed to ClO2 gas generated from 1.0 or 1.5 mL ClO2 solution in a sealed container at 50 or 60 °C (43% relative humidity) for up to 10 h. The concentration of ClO2 gas peaked at 354-510 and 750-786 ppm within 0.5 h upon deposition of 1.0 and 1.5 mL of aqueous ClO2, respectively, and gradually decreased thereafter. Population of S. Enteritidis on almonds treated at 50 °C decreased to 1.70-2.32 log cfu/sample within 1 h of exposure to ClO2 gas and decreased to below the detection limit (1.7 log cfu/sample) at all ClO2 concentrations after 8 h. At 60 °C, the microbial population fell below the detection limit within 1 h, regardless of the volume of ClO2 solution supplied. Microbial survival on almonds treated with ClO2 gas and stored at 12 or 25 °C was observed for up to 8 weeks and the organism was not recovered from the almonds treated for 10 h and stored at 12 °C for 2-8 weeks. The lightness (L value) and redness (a value) of almonds treated for 10 h were not changed by ClO2 gas treatment, but yellowness (b value) increased. Results showed that Salmonella on almonds was successfully inactivated by ClO2 gas treatment and the microbial survival did not occur during storage.
Subject(s)
Chlorine Compounds/pharmacology , Food Preservation/methods , Food Preservatives/pharmacology , Oxides/pharmacology , Prunus dulcis/microbiology , Salmonella enteritidis/drug effects , Chlorine Compounds/chemistry , Food Preservation/instrumentation , Food Storage , Gases/pharmacology , Microbial Viability/drug effects , Nuts/microbiology , Oxides/chemistry , Salmonella enteritidis/growth & developmentABSTRACT
The aim of this study was to investigate the effect of water activity (aw) on inactivation of Listeria monocytogenes using gaseous chlorine dioxide (ClO2 (g)) under room temperature. Surface-inoculated tryptic soy agar (TSA) plates adjusted to 9 different water activity levels ranging from 0.994 to 0.429 were used as samples exposed to ClO2 (g) at 150, 250, and 350 ppm for different durations of treatment time. Results showed that the antimicrobial effect of ClO2 (g) significantly decreases as the aw level and ClO2 (g) concentration decrease. Nonlinear models, such as the modified Chick model and the Weibull model, were used to describe the inactivation kinetics of L. monocytogenes. The results showed that the modified Chick model, which is based on chemical reaction kinetics, was more suitable to describe the inactivation of L. monocytogenes (RMSE < 0.5 log CFU/g) than the Weibull model (RMSE < 1.0 log CFU/g). A multiple regression model was developed for the describing the effect of aw and ClO2 (g) concentration on bacterial inactivation. The results of this study may be used to design ClO2 (g) treatment processes to inactivate L. monocytogenes in low-moisture foods.
Subject(s)
Chlorine Compounds/pharmacology , Disinfectants/pharmacology , Listeria monocytogenes/drug effects , Listeria monocytogenes/growth & development , Oxides/pharmacology , Water/analysis , Chlorine Compounds/chemistry , Colony Count, Microbial , Disinfectants/chemistry , Gases/pharmacology , Kinetics , Listeria monocytogenes/chemistry , Oxides/chemistry , Water/metabolismABSTRACT
The objectives of this study were to investigate the effects of processing parameters (relative humidity (RH), temperature, and exposure time) on the ethylene oxide (EtO) microbial inactivation of Salmonella spp. and to evaluate Enterococcus faecium NRRL B2354 as a suitable surrogate for Salmonella inactivation on cumin seeds. Five grams of cumin seeds inoculated with either Salmonella or E. faecium were treated with EtO at different temperatures (46, 53, and 60 °C) and RH (30, 40, and 50%) levels for different exposure time to investigate the effects of process parameters on the microbial inactivation. The Weibull model fit the survival data of both bacteria with a shape parameter p < 1, which showed a tailing effect with concave shape indicating that the sensitive cells were inactivated first, and the sturdy ones survived at low RH treatment conditions. In general, the log reductions of both bacteria on cumin seeds increased with the increasing RH and temperature for EtO treatment. RH is a critical factor for successful EtO inactivation treatment. RH must be higher than 40% to implement a successful and efficient EtO decontamination of cumin seeds. E. faecium consistently showed lower log reductions than those of Salmonella under all EtO treatment conditions investigated in this study, demonstrating that E. faecium is a suitable surrogate for Salmonella. Twenty minutes of EtO treatment at 50% RH achieved ~5 log reductions of both bacteria at all three temperatures. A response surface model was developed to predict the log reductions of both bacteria under different treatment conditions and the contour plots representing log reductions were created. Inactivation is positively correlated to temperature and RH. Therefore, a higher temperature is required to achieve the desired log reduction at lower RH and vice versa. The developed response surface model is a valuable tool for the spice industry in identifying the possible combinations of EtO process parameters (temperature, RH, and exposure time) required to achieve a desired microbial reduction of Salmonella for ensuring microbial food safety of spices.
Subject(s)
Cuminum/microbiology , Enterococcus faecium/drug effects , Ethylene Oxide/chemistry , Ethylene Oxide/pharmacology , Food Preservation/methods , Salmonella enterica/drug effects , Colony Count, Microbial , Enterococcus faecium/growth & development , Food Preservation/instrumentation , Food Preservatives/chemistry , Food Preservatives/pharmacology , Food Safety , Gases/pharmacology , Microbial Viability/drug effects , Salmonella enterica/growth & development , Seeds/microbiology , Spices/microbiology , TemperatureABSTRACT
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.
Subject(s)
Cold Temperature , Ethanol/pharmacology , Food Preservation/methods , Food Preservatives/pharmacology , Food Quality , Food Storage/methods , Fruit/drug effects , Gases/pharmacology , Vitis/drug effects , Aquaporins/genetics , Fruit/genetics , Gene Expression/drug effects , Maillard Reaction/drug effects , Plant Proteins/genetics , Transcription Factors/genetics , Transcription, Genetic/drug effects , Vitis/genetics , VolatilizationABSTRACT
In recent years, various biomimetic materials capable of forming gaseous plastron on their surfaces have been fabricated and widely used in various disciplines and fields. In particular, on submerged surfaces, gaseous plastron has been widely studied for antifouling applications due to its ecological and economic advantages. Gaseous plastron can be formed on the surfaces of various natural living things, including plants, insects, and animals. Gaseous plastron has shown inherent anti-biofouling properties, which has inspired the development of novel theories and strategies toward resisting biofouling formation on different surfaces. In this review, we focused on the research progress of gaseous plastron and its antifouling applications.
Subject(s)
Aquatic Organisms , Biofouling , Biomimetics , Gases , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Biochemical Phenomena , Gases/chemistry , Gases/pharmacology , Hydrophobic and Hydrophilic Interactions , Surface PropertiesABSTRACT
We followed a comparative approach to investigate how heavy vacuum gas oil (HVGO) affects the expression of genes involved in biosurfactants biosynthesis and the composition of the rhamnolipid congeners in Pseudomonas sp. AK6U. HVGO stimulated biosurfactants production as indicated by the lower surface tension (26 mN/m) and higher yield (7.8 g/L) compared to a glucose culture (49.7 mN/m, 0.305 g/L). Quantitative real-time PCR showed that the biosurfactants production genes rhlA and rhlB were strongly upregulated in the HVGO culture during the early and late exponential growth phases. To the contrary, the rhamnose biosynthesis genes algC, rmlA and rmlC were downregulated in the HVGO culture. Genes of the quorum sensing systems which regulate biosurfactants biosynthesis exhibited a hierarchical expression profile. The lasI gene was strongly upregulated (20-fold) in the HVGO culture during the early log phase, whereas both rhlI and pqsE were upregulated during the late log phase. Rhamnolipid congener analysis using high-performance liquid chromatography-mass spectrometry revealed a much higher proportion (up to 69%) of the high-molecularweight homologue Rha-Rha-C10-C10 in the HVGO culture. The results shed light on the temporal and carbon source-mediated shifts in rhamonlipids' composition and regulation of biosynthesis which can be potentially exploited to produce different rhamnolipid formulations tailored for specific applications.
Subject(s)
Bacterial Proteins/metabolism , Gases/pharmacology , Glycolipids/biosynthesis , Glycosyltransferases/metabolism , Oils, Volatile/pharmacology , Pseudomonas/metabolism , Quorum Sensing , Pseudomonas/drug effects , Pseudomonas/growth & development , Rhamnose/metabolism , Surface-Active Agents/pharmacology , VolatilizationABSTRACT
AIMS: This study investigated the efficacy of hydrogen peroxide vapour (HPV) at inactivating hazard group 3 bacteria that have been presented dried from their growth medium to present a realistic challenge. METHODS AND RESULTS: Hydrogen peroxide vapour technology (Bioquell) was used to decontaminate a class III microbiological safety cabinet containing biological indicators (BIs) made by drying standard working suspensions of the following agents: Bacillus anthracis (Ames) spores, Brucella abortus (strain S99), Burkholderia pseudomallei (NCTC 12939), Escherichia coli O157 ST11 (NCTC 12079), Mycobacterium tuberculosis (strain H37Rv) and Yersinia pestis (strain CO92) on stainless steel coupons. Extended cycles were used to expose the agents for 90 min. The HPV cycle completely inactivated B. anthracis spores, B. abortus, B. pseudomallei, E. coli O157 and Y. pestis when BIs were processed using quantitative and qualitative methods. Whilst M. tuberculosis was not completely inactivated, it was reduced by 4 log10 from a starting concentration of 106 colony-forming units. CONCLUSIONS: This study demonstrates that HPV is able to inactivate a range of HG3 agents at high concentrations with associated organic matter, but M. tuberculosis showed increased resistance to the process. SIGNIFICANCE AND IMPACT OF THE STUDY: This publication demonstrates that HPV can inactivate HG3 agents that have an organic load associated with them. It also shows that M. tuberculosis has higher resistance to HPV than other agents. This shows that an appropriate BI to represent the agent of interest should be chosen to demonstrate a decontamination is successful.
Subject(s)
Containment of Biohazards/methods , Decontamination/methods , Disinfectants/pharmacology , Gases/pharmacology , Hydrogen Peroxide/pharmacology , Bacteria/drug effects , Containment of Biohazards/instrumentation , Drug Resistance, Bacterial , Environmental Biomarkers/drug effects , Stainless SteelABSTRACT
The climate-active gas methane is generated both by biological processes and by thermogenic decomposition of fossil organic material, which forms methane and short-chain alkanes, principally ethane, propane and butane. In addition to natural sources, environments are exposed to anthropogenic inputs of all these gases from oil and gas extraction and distribution. The gases provide carbon and/or energy for a diverse range of microorganisms that can metabolize them in both anoxic and oxic zones. Aerobic methanotrophs, which can assimilate methane, have been considered to be entirely distinct from utilizers of short-chain alkanes, and studies of environments exposed to mixtures of methane and multi-carbon alkanes have assumed that disparate groups of microorganisms are responsible for the metabolism of these gases. Here we describe the mechanism by which a single bacterial strain, Methylocella silvestris, can use methane or propane as a carbon and energy source, documenting a methanotroph that can utilize a short-chain alkane as an alternative to methane. Furthermore, during growth on a mixture of these gases, efficient consumption of both gases occurred at the same time. Two soluble di-iron centre monooxygenase (SDIMO) gene clusters were identified and were found to be differentially expressed during bacterial growth on these gases, although both were required for efficient propane utilization. This report of a methanotroph expressing an additional SDIMO that seems to be uniquely involved in short-chain alkane metabolism suggests that such metabolic flexibility may be important in many environments where methane and short-chain alkanes co-occur.
Subject(s)
Beijerinckiaceae/metabolism , Gases/metabolism , Methane/metabolism , Propane/metabolism , Beijerinckiaceae/enzymology , Beijerinckiaceae/genetics , Beijerinckiaceae/growth & development , Carbon/metabolism , Enzyme Induction/drug effects , Gases/pharmacology , Gene Expression Regulation, Bacterial/drug effects , Global Warming , Methane/pharmacology , Mixed Function Oxygenases/genetics , Mixed Function Oxygenases/metabolism , Multigene Family/genetics , Propane/pharmacologyABSTRACT
BACKGROUND: For medical purposes, plasma can be generated from inert gaseous sources in a device by ultra-high-frequency generators and emitted to target tissue at a pulse duration in the milliseconds. OBJECTIVE: To evaluate argon and nitrogen plasma pulse-induced tissue reactions in the skin and skin appendages of an in vivo animal model. METHODS: Argon and nitrogen plasma pulses were non-invasively delivered to in vivo rat skin at various experimental settings. Specimens were histologically evaluated following hematoxylin and eosin and Masson's trichrome staining. RESULTS: At low-energy settings of 1.0, 1.5, and 2.0 J, nitrogen plasma treatments generated noticeable tissue coagulation at the depths of 31.5 ± 8.3, 94.9 ± 16.9, and 171.6 ± 19.7 µm, respectively, at Day 0. At high-energy settings of 2.5 and 3.0 J, nitrogen plasma treatments generated marked tissue coagulation at the depths of 381.7 ± 33.6 µm and 456.3 ± 75.7 µm, respectively, at Day 0. CONCLUSIONS: Treatment with argon plasma induces microscopic changes in the epidermis, dermis, and sebaceous glands without generating excessive thermal injury, whereas that with nitrogen plasma elicits energy-dependent thermal coagulation in the epidermis and dermis with remarkable neocollagenesis.
Subject(s)
Gases/pharmacology , Skin/drug effects , Skin/pathology , Animals , Male , Rats , Rats, Sprague-DawleyABSTRACT
Gaseous treatments with ClO2 and O3 on low-moisture foods (LMFs) have been reported for their efficient bacterial reduction without affecting the external quality of food. However, these studies were conducted on a small scale, which limits their application to LMF industries. We aimed to evaluate the effectiveness of gaseous antimicrobial intervention with ClO2 or O3 to reduce foodborne pathogens (Shiga toxin-producing Escherichia coli, serovars of Salmonella enterica, and Listeria monocytogenes) inoculated on almonds and peppercorns maintained under various conditions. Almonds were treated for over 4 or 6 h. Peppercorns were treated for over 2.5 or 4 h. Gaseous O3 treatment was used for 6 h on almonds and 2 or 4 h on peppercorns. Additionally, the effects of relative humidity (RH) during the treatment of peppercorns and post-treatment heating on almonds were evaluated. Heating at 65 °C post-ClO2 treatment yielded the highest bacterial log reduction of 4.6 CFU/g on almonds, while 80% RH resulted in 3.7-log bacterial reduction on peppercorns. Gaseous O3 resulted in maximum log reductions of 1.3 and 2.5 CFU/g on almonds and peppercorns, respectively. No visual damage was observed. In conclusion, ClO2 was more efficient than O3 and the treatment can be incorporated into industrial practices.
Subject(s)
Chlorine Compounds/pharmacology , Food Preservation/methods , Food Preservatives/pharmacology , Oxides/pharmacology , Ozone/pharmacology , Piper nigrum/microbiology , Prunus dulcis/microbiology , Chlorine Compounds/chemistry , Food Microbiology , Food Preservation/instrumentation , Food Preservatives/chemistry , Gases/chemistry , Gases/pharmacology , Listeria monocytogenes/drug effects , Listeria monocytogenes/growth & development , Oxides/chemistry , Ozone/chemistry , Salmonella enterica/drug effects , Salmonella enterica/growth & development , Seeds/microbiologyABSTRACT
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⯵L/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]â¯=â¯0.3750). A combination of thyme thymol and cinnamon bark EO gases also had a synergistic effect (FICIâ¯=â¯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⯵L/mL, caused a significant (Pâ¯≤â¯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.
Subject(s)
Anti-Bacterial Agents/pharmacology , Listeria monocytogenes/drug effects , Oils, Volatile/pharmacology , Origanum/chemistry , Raphanus/microbiology , Thymol/pharmacology , Thymus Plant/chemistry , Anti-Bacterial Agents/chemistry , Cinnamomum zeylanicum/chemistry , Culture Media/chemistry , Culture Media/metabolism , Drug Synergism , Gases/pharmacology , Listeria monocytogenes/growth & development , Microbial Sensitivity Tests , Oils, Volatile/chemistry , Plant Oils/chemistry , Plant Oils/pharmacology , Raphanus/growth & development , Thymol/chemistryABSTRACT
The high-pressure gas (HPG) method with carbon monoxide (CO) and oxygen (O2) mixture maintains the preserved rat heart function. The metabolites of rat hearts preserved using the HPG method (HPG group) and cold storage (CS) method (CS group) by immersion in a stock solution for 24 h were assessed to confirm CO and O2 effects. Lactic acid was significantly lower and citric acid was significantly higher in the HPG group than in the CS group. Moreover, adenosine triphosphate (ATP) levels as well as some pentose phosphate pathway (PPP) metabolites and reduced nicotinamide adenine dinucleotide phosphate (NADPH) were significantly higher in the HPG group than in the CS group. Additionally, reduced glutathione (GSH), which protects cells from oxidative stress, was also significantly higher in the HPG group than in the CS group. These results indicated that each gas, CO and O2, induced the shift from anaerobic to aerobic metabolism, maintaining the energy of ischemic preserved organs, shifting the glucose utilization from glycolysis toward PPP, and reducing oxidative stress. Both CO and O2 in the HPG method have important effects on the ATP supply and decrease oxidative stress for preventing ischemic injury. The HPG method may be useful for clinical application.