Characterization and application of exposure biomarkers of polycyclic aromatic hydrocarbons in diesel exhaust / 环境与职业医学

Diesel exhaust (DE), Group 1 carcinogen, is an important source of air pollutants. Studies show that DE exposure associates with elevated incidences of respiratory and cardiovascular diseases. The toxic effects of DE are closely related to its components. Polycyclic aromatic hydrocarbons (PAHs) are one of the main toxic components in DE and are often used as human exposure biomarkers to DE. However, the exposure assessment of DE using PAHs as biomarkers could be interfered due to the other sources of PAHs. Therefore, identification of highly specific and reliable PAHs sourced biomarkers of DE exposure has become a hotspot of current research. New biomarkers of DE may play an important role in determining human exposure to DE and establishing dose-response relationship of DE exposure and health outcomes of interest. This paper focused on current progress in terms of PAHs sourced biomarkers of human exposure to DE with the following aims: (1) to clarify the types of PAHs sourced biomarkers to DE; (2) to explore the applicability and limitations of PAHs sourced biomarkers for DE exposure assessment in occupational exposure and environmental exposure analysis; and (3) to summarize the analysis methods for PAHs sourced exposure biomarkers in human urine samples and compare the advantages and disadvantages of different analytical methods.

Research progress on effect and mechanism of diesel exhaust particles on asthma / 环境与职业医学

As a source of traffic-related air pollution, diesel particulate matter (DPM) associate with a variety of lung-related diseases, but there is no systematic review of the relationship between DPM and the development and progression of asthma. This article reviewed the relationship between DPM and asthma, the effect and mechanism of DPM on airway inflammation and remodeling in asthma, and illustrated that DPM exposure may participate in airway inflammation and remodeling through oxidative stress, immune regulation and regulation of lung and intestinal microecology, so as to promote the development and progression of asthma.

Research progress in epigenetic toxicity of diesel exhausts / 环境与职业医学

Diesel exhaust (DE) can enter the organism body and cause multiple organ damage. DE contains particles that can be suspended in the air for a long time. Epigenetic regulation is a post transcriptional regulation change that does not involve DNA sequence changes. Many evidences showed that DE can affect the normal physiological functions of multiple organs and systems through epigenetic changes, thus regulating the occurrence and development of multiple diseases. This paper reviewed the research progress of DNA methylation and non-coding RNA in the biological harmful effects of DE. This will provide a basis for the safety evaluation, health risk assessment, and management of DE.

Application progress of air-liquid interface exposure technology in respiratory system toxicity induced by diesel exhaust in vitro / 环境与职业医学

Diesel exhaust (DE) is an important pollution source widely existing in the living and production environment, which is closely related to the health of the public and occupational groups. The International Agency for Research on Cancer has classified DE as a Group 1 carcinogen. Considering the negative health impacts on the respiratory system due to DE exposure in vitro, it is crucial to apply reliable test systems allowing accurate assessment of the biological effects of DE. The exposure technology of respiratory system in vitro is considered as one of the feasible measures to implement the 3R (reduce, refine, and replace) principle in animal experiments. Compared with the traditional submerged culture in vitro models, the air-liquid interface (ALI) exposure technology has the advantages including fewer influencing factors, easier exposure condition control, and shorter exposure cycle. ALI has become an important tool to study molecular events associated with physiology and pathology of respiratory system, and action modes and interactions of different cell types. Also, ALI has been increasingly widely used because it can simulate the actual processes of human respiratory system cells and/or tissues to DE exposure. This review was intended to introduce the development and advantages of ALI exposure technology, and further summarized the application progress of ALI exposure technology in studying the respiratory toxicity induced by DE exposure in vitro, so as to provide new ideas and pathways for the use of ALI exposure technology in the study of biomarkers and mechanisms of respiratory toxicity associated with DE exposure, and provide basic data to screen and promote biomarkers for exposed populations.

Diesel exhaust inhalation exposure induced toxicity on olfactory bulb in mice through inflammatory response mediated by activating glial cells / 环境与职业医学

Background Air pollution is related to the occurrence and development of mental diseases. Olfactory bulb damage might be the potential prodromal symptom and sign of these diseases. The toxicity of diesel exhaust (DE), one of the main sources of air pollution, on olfactory bulb and the underlying mechanisms remain to be elucidated. Objective To explore the toxicity of DE on mouse olfactory bulb and underlying mechanisms. Methods A total of 40 C57BL/6 mice were randomly divided into four groups for exposure to DE by systemic inhalation: control group (filtered air), low exposure group (750 μg·m−3 DE), medium exposure group (1500 μg·m−3 DE), and high exposure group (3000 μg·m−3 DE). The mouse inhalation exposure to DE was performed 1 h per day for 28 d. HE staining was performed to observe pathological changes in mouse olfactory bulb tissue. TUNEL assay was used to observe apop-tosis in olfactory bulb. Kyoto Encyclopedia of Genes and Genomes (KEGG) was exhibited to explore potential mechanisms of olfactory bulb damage associated with DE. Quantitative real-time PCR (qPCR) was used to determine mRNA expression levels of inflammatory factors including tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Immunofluorescence staining was conducted to observed the microglia and astrocyte activation in olfactory bulb. Results The HE staining results showed that the number of periglomerular cells in the glomerular layer of olfactory bulb decreased in a dose-dependent manner, and the cells in the granule cell layer of olfactory bulb became disordered after DE exposure. The TUNEL staining showed that TUNEL positive cells in olfactory bulb tissue and neuronal apoptosis increased in the exposed groups compared with the control group (P＜0.05). The KEGG pathway analysis showed that DE associated with significant enrichment of TNF signaling pathway in olfactory bulb tissue. The qPCR results showed that the TNF-α relative expression level significantly increased by 67% and the IL-6 relative expression level by 340% in the DE high exposure dose group compared with the control group (P＜0.05). According to the immunofluorescence staining results, the numbers of activated microglia and astrocytes in olfactory bulb tissue significantly increased in the DE high exposure group, the relative fluorescence intensity of ionized calcium binding adaptor molecule 1 (IBA-1) increased by 120%, the granule cell layer relative fluorescence intensity of glial fibrillary acidic protein (GFAP) increased by 400%, and the glomerular layer relative fluorescence intensity of GFAP increased by 240% than those in the control group (P＜0.05). Conclusion Inhalation exposure to DE can lead to glial cell activation including microglia and astrocytes in olfactory bulb tissue by activating inflammatory pathways and releasing inflammatory factors TNF-α and IL-6, leading to neuronal apoptosis in olfactory bulb tissue.

Roles of aryl hydrocarbon receptors in diesel exhaust inhalation-induced cardiopulmonary toxicities during initiation of pulmonary respiration in chicken / 环境与职业医学

Background Due to the limited availability of established research models, very few studies addressed the health effects and underlying mechanisms following exposure to diesel exhaust during the initiation of pulmonary respiration. It is highly demanded to elucidate such health effects and underlying mechanisms, so as to exert protective measures during the early stages of life. Objective To evaluate the health effects of diesel exhaust very-early-in-life inhalation in hatchling chicken with a novel chicken embryo air cell inhalation exposure model, and to explore the potential roles of aryl hydrocarbon receptor signaling pathways in the observed effects with a specific aryl hydrocarbon receptor inhibitor. Methods Fertilized chicken eggs were assigned into five groups randomly (15 eggs per group): control group, air control group, aryl hydrocarbon receptor inhibitor (PDM2) group, diesel exhaust group, and diesel exhaust + aryl hydrocarbon receptor inhibitor (PDM2) group. Fertilized eggs were incubated with standard procedure. At embryonic day 17 (ED17), aryl hydrocarbon receptor inhibitor was administered to the corresponding animals. During embryonic day 18-19 (ED18-19), chicken embryos were exposed to diesel exhaust via air cell inhalation, then placed back to incubator until hatch. The air control group received clean air infusion during ED18-19, while the control group did not receive any treatment. Within 24 h post-hatch, 26 hatchling chickens were anesthetized with sodium pentobarbital, subjected to electrocardiography, and sacrificed to harvest tissue samples of heart and lung. Cardiopulmonary toxicities were evaluated by histopathology, and potential changes in the protein expression levels of aryl hydrocarbon receptor pathway molecule cytochrome P450, family 1, subfamily A, polypeptide 1 (CYP1A1) and fibrosis-related pathway molecule phosphorylated SMAD family member 2 (pSMAD2) were assessed by Western blotting. The remaining 29 hatchling chickens were reared until two weeks old, and then subjected to identical treatments. Results The inhalation exposure to diesel exhaust at initiation of pulmonary respiration resulted in thickened right ventricular wall (by 220.3% relative to the control group, same hereafter) and elevated heart rate (17.4%) in one-day-old hatchling chickens. Although no remarkable fibrotic lesions were observed at this point, the expression levels of CYP1A1 and phosphorylation levels of SMAD2 in the lung tissues significantly increased (by 81.3% and 71.6%, respectively). Such changes were effectively abolished by the aryl hydrocarbon receptor inhibitor PDM2 pretreatment. In the two-week-old animals, the thickened right ventricular wall (by 339.3%) and elevated heart rate (by 18.9%) persisted, and significant fibrotic lesions were observed in the lung tissue samples under Masson staining. Again, the aryl hydrocarbon receptor inhibitor PDM2 pretreatment effectively abolished such changes. In addition, no statistically significant changes in CYP1A1 expression levels were observed in the two-week-old chicken lung samples, and a remarkable down-regulation of SMAD2 phosphorylation was observed. The aryl hydrocarbon receptor inhibitor PDM2 pretreatment independently decreased the phosphorylation levels of SMAD2 in the two-week-old chicken lung samples. Conclusion Inhalation exposure to diesel exhaust at initiation of pulmonary respiration could result in persistent cardiopulmonary injury in hatchling chickens, and the underlying mechanism might be associated with the regulation of pSMAD2 by the aryl hydrocarbon receptor signaling pathway.

Regulating anaerobic metabolism and promoting myocardial ischemia-hypoxia injury by diesel particulate matter and its key component benzoapyrene via targeting oxygen sensors / 环境与职业医学

Background The exposure to diesel particulate matter (DPM) and its polycyclic aromatic hydrocarbons (PAH) is closely related to the morbidity and mortality of ischemic heart disease (IHD). However, it is unclear what key components and targets of DPM exposure involve in myocardial ischemia-hypoxia injury and associated mechanisms. Objective To identify key PAH components of DPM that act on myocardial hypoxic injury, andclarify the role of oxygen sensors-regulated anaerobic metabolism in DPM and key components-induced hypoxic injury and the targets of the key PAH components. Methods Human cardiomyocyte cell line AC16 cells were exposed to 0, 1, 5, and 10 μg·mL−1 DPM in a high glucose DMEM medium with 10% fetal bovine serum (FBS) (HGM) or low FBS (0.5%) in high glucose DMEM medium (LFM), for 12 h under 2% O2, and expression of hypoxia-inducible factor-1α (HIF-1α), Bax, and Cleaved-caspase3 was determined by Western blotting. Under normal condition, the cell viability was detected after PAH exposure for 12 h. Under the condition of ischemia-hypoxia model, cells were exposed to 0, 0.005, 0.5, and 5 µg·mL−1 PAH for 12 h, and the protein expression of HIF-1α, Bax, and Cleaved-caspase3 was determined. After exposure to DPM or PAH for 12 h, the contents of pyruvate and lactate in cells were detected. Pretreatment with glycolysis inhibitor GSK2837808A was used to explore the role of glycolysis in DPM and benzo[a]pyrene (BaP)-induced hypoxia injury. A molecular docking technique was used to analyze the binding affinity between PAH and oxygen sensors (prolyl hydroxylase domain-containing protein 2, PHD2, and factor-inhibiting hypoxia-inducible factor 1, FIH1), and the protein levels of PHD2, FIH1, and hydroxyl-HIF-1-alpha (OH-HIF-1α) after the DPM or BaP treatment were further determined. Results Under hypoxia, DPM exposure in the LFM induced the expression of HIF-1α, Bax, and Cleaved-caspase3 (P<0.01). Therefore, hypoxia and LFM were selected as the basic ischemia and hypoxia condition. Except for anthracene (Ant) (P>0.05), other PAH decreased cell viability when the concentration was above 1 μg·mL−1 (P<0.05). All concentrations of BaP induced the expression of HIF-1α protein (P<0.05), and the protein levels of Bax and Cleaved-caspase3 were up-regulated after the 0.5 and 5 µg·mL−1 BaP exposure (P<0.01). After exposure to DPM (1, 5 and 10 μg·mL−1) or BaP (0.5 and 5 μg·mL−1), the intracellular pyruvate and lactate contents increased (P<0.05). The glycolysis inhibitor co-treatment decreased the levels of HIF-1α, Bax, and Cleaved-caspase3 proteins compared with the DPM or BaP exposure group for 12 h (P＜0.05). The binding abilities of the five PAHs to the oxygen sensors PHD2 and FIH1 were strong, and BaP was the strongest. Although the DPM or BaP exposure had no effects on the protein levels of PHD2 and FIH1 in AC16 cells (P＜0.05), the protein level of OH-HIF-1α was decreased (P＜0.01). Conclusion BaP exposure can promote hypoxia and injury of myocardial cells and is the key PAH component of DPM that induces myocardial ischemia and hypoxia injury. BaP exposure inhibits the hydroxylation function of PHD2 on HIF-1α by combining with PHD2, decreases the level of OH-HIF-1α and induces HIF-1α accumulation. And then HIF-1α promotes anaerobic metabolism and accelerates ischemia and hypoxia injury of myocardial cells.

Pay attention to health hazards of diesel exhaust exposure, and strengthen occupational protection / 环境与职业医学

The air pollution related health hazards have been a major public health issue for a long time. As an important source of air pollution, diesel exhaust (DE) exposure associates with serious adverse health outcomes. Apart from the exposure in general population, extensive occupational DE exposure populations are reported in many industries, such as transportation, mining, shipping, and construction. Therefore, the studies for internal exposure levels, biomarkers, and toxic mechanisms of DE in occupational population are critical for protecting human from DE-posed health hazards. This special column published some novel findings involving DE exposure (internal & external exposure level), multiple biological effects, toxicity mechanisms, key molecular events, and crucial biomarkers. These studies will provide scientific data for controlling DE associated occupational health hazards, formulating effective DE pollution control strategies, and provide a new scientific perspective and evidence for health risk assessment and prevention.

Análisis de la mezcla de alcoholes en motor diésel

Debido a que el futuro del petróleo es incierto, en la búsqueda de los combustibles alternativos se ha encontrado que el alcohol es un fuerte candidato como combustible; los alcoholes inferiores más representativos son el metanol y el etanol, los cuales han demostrado en general baja miscibilidad, por lo que pueden generar una separación de fases al ser mezclados después de un cierto tiempo. La única manera de emplearlos en un motor diésel es mezclándolos con biodiésel o con surfactantes. Por el contrario, los alcoholes superiores tienen características más adecuadas para ser mezclados o empleados en el motor diésel. Por su parte, los éteres son una buena opción cuando se trate de combustión piloto en que se considere emplear combustibles gaseosos como el biogás o el syngas en motor diésel dual. En esta investigación se exploran las alternativas que existen para mejorar las características del alcohol, por ejemplo, mezclarlo con biodiésel, biogás, agua o nanopartículas, y también se analizan las emisiones que se producen con las mezclas generadas. El objetivo es indagar las diferencias entre los alcoholes inferiores y los alcoholes superiores de cadena larga, así como las mezclas que se pueden generar para mejorar el rendimiento del motor. Los resultados afirman que los alcoholes de cadena larga tienen mejores propiedades físico-químicas que los alcoholes de cadena corta; el butanol es el único combustible que puede ser transportado y almacenado en las mismas redes de tuberías actuales de los productos petroleros existentes. También se cuenta con la opción de usar el alcohol como combustible piloto en un motor diésel dual; esto puede servir para aplicar una enorme variedad de combustibles tanto líquidos como gaseosos, lo cual hace que las opciones en su aplicación se incrementen. Como conclusión, se recomienda explorar nuevas mezclas analizando sus sinergias con varios combustibles alternativos. La posibilidad de realizar el diesterol-BED genera resultados muy alentadores, por lo que se recomienda seguir haciendo análisis sobre esa línea para encontrar la mezcla óptima.

As the future of oil is uncertain and in the search for alternative fuels, it has been found that alcohol is a strong candidate as a fuel. The most representative lower alcohols are methanol and ethanol, which have generally demonstrated low miscibility so that they can generate phase separation when mixed after a certain period of time. The only way to use them in a diesel engine is to mix them with biodiesel or surfactants. By contrast, higher alcohols have more suitable characteristics to be mixed or used in the diesel engine. In the case of ethers they are a good option when it comes to pilot combustion considering using gaseous fuels such as biogas or syngas in dual diesel engine. This research explores the alternatives that exist to improve the characteristics of alcohol as it can be mixed with biodiesel, biogas, water or nanoparticles and also analyzes the emissions that are generated with the mixtures. The aim of this research is to explore the differences between lower alcohols and long chain upper alcohols, as well as the mixtures that can be generated to improve engine performance. The results of this research claim that long-chain alcohols have better physico-chemical properties than short-chain alcohols, butanol being the only fuel that can be transported and stored in the same current pipeline networks of existing oil products. There is also the option to use alcohol as a pilot fuel in a dual diesel engine. The latter can be used to apply a huge variety of both liquid and gaseous fuels, this makes the options in its application increase. As a conclusion of this work, it is recommended to explore new mixtures analyzing their synergies with various alternative fuels. The possibility of performing diesterol-BED generates very encouraging results, therefore it is recommended to continue to perform analyses on that line to find the optimal mixture.

Na busca por combustíveis alternativos porque o futuro do petróleo é incerto, verificou-se que o álcool é um forte candidato como combustível, onde os álcoois inferiores mais representativos são o metanol e o etanol, que, em geral, demonstraram baixa miscibilidade, de modo que podem gerar separação de fase quando misturadas após um determinado período de tempo, a única forma de as utilizar num motor diesel é misturá-las com biodiesel ou tensioactivos, pelo contrário, os álcoois superiores têm características mais adequadas para serem misturados ou utilizados no motor diesel, no caso dos éteres, são uma boa opção quando se trata de combustão piloto, considerando a utilização de combustíveis gasosos, como biogás ou gás de síntese em motores a diesel duplos, esta pesquisa explora as várias alternativas que existem para melhorar as características do álcool, pois pode ser misturado com biodiesel, biogás, água ou nanopartículas e também analisa as emissões que são geradas com as misturas geradas, O objetivo desta pesquisa é explorar as diferenças entre álcoois inferiores e álcoois superiores de cadeia longa, bem como as misturas que podem ser geradas para melhorar o desempenho do motor. Os resultados desta pesquisa afirmam que os álcoois de cadeia longa têm melhores propriedades físico-químicas do que os álcoois de cadeia curta, sendo o butanol o único combustível que pode ser transportado e armazenado nas mesmas redes de gasodutos atuais que os produtos petrolíferos existentes, há também a opção de usar álcool como combustível piloto em um motor diesel duplo, Este último pode ser usado para aplicar uma enorme variedade de combustíveis líquidos e gasosos, o que aumenta as opções em sua aplicação. Como conclusão deste trabalho recomenda-se explorar novas misturas analisando suas sinergias com vários combustíveis alternativos, a possibilidade de realizar diesterol-BED gera resultados muito encorajadores, portanto, recomenda-se continuar a realizar análises nessa linha para encontrar a mistura ideal.

Isolation and characterization of hydrocarbon-degrading bacteria from gas station leaking-contaminated groundwater in the Southern Amazon, Brazil / Isolamento e caracterização de bactérias degradadoras de hidrocarbonetos de água subterrânea contaminada por vazamentos em posto de combustível no sul da Amazônia, Brasil

Abstract Twenty-three hydrocarbon-degrading bacteria strains were isolated from gas station leaking-contaminated groundwater located in the Southern Amazon, Brazil. Based on hydrocarbon (diesel, hexadecane, benzene, toluene and xylene) degradation ability, two strains were selected for further study. The amplification and sequencing of the 16S rRNA gene showed that these two strains belonged to the genus Bacillus (Bacillus sp. L26 and Bacillus sp. L30). GC-MS analysis showed that strain L30 was the most effective in degrading n-alkane (C10-C27) from diesel after 7 days of cultivation in mineral medium. Both strains produced biosurfactants and showed emulsification activity, specially the strain L30. Alkane hydroxylase gene (group III), which is important for alkane biodegradation, was present in strains. As a result, this study indicated that these bacteria could have promising applications in hydrocarbon bioremediation.

Resumo Vinte e três linhagens bacterianas degradadoras de hidrocarbonetos foram isoladas de água subterrânea contaminada por vazamento em posto de combustível no sul da Amazônia, Brasil. Com base na habilidade de degradar hidrocarbonetos (diesel, hexadecano, benzeno, tolueno e xileno), duas linhagens foram selecionadas para estudos posteriores. A amplificação e sequenciamento do gene 16S rRNA demonstrou que essas linhagens pertencem ao gênero Bacillus (Bacillus sp. L26 and Bacillus sp. L30). Análises de GC-MS mostraram que a linhagem L30 foi mais eficiente em degradar n-alcanos (C10-C27) presentes no diesel, após 7 dias de cultivo em meio mineral. Ambas as linhagens produziram biossurfactantes e apresentaram atividade emulsificante, especialmente a linhagem L30. O gene alcano hidroxilase (grupo III), o qual é importante para degradação de alcanos, foram detectados nas linhagens. Como resultado, este estudo indicou que essas linhagens bacterianas podem ser promissoras se aplicadas em processos de biorremediação.

Effects of Mesenchymal Stem Cells and Their Derived Microvesicles on Pulmonary Toxicity Induced by Petrol Exhaust Nanoparticle; Histological and Immuno-Histochemical Study

Background: Diesel vehicles exhaust contains toxic nanoparticles that drastically affect lung tissue due to their direct cytotoxic effects, induction of oxidative stress, inflammatory signaling pathways and DNA damage. Mesenchymal stem cells (MSCs) exhibit anti-inflammatory effects and efficient regenerative capacity in chronic lung diseases. Objectives: Evaluation of the effects of MSCs and MSCs-derived micro vesicles (MSCs-MVs) on pulmonary toxicity induced by diesel exhaust nanoparticles (DENPs). Materials and Methods: Sixty male rats were equally divided into: Group I (Control rats), Group II (DENPs group) received repeated doses of DENPs (180μg/rat) intratracheally every other day for 6 days, Group III (MSCs group) received MSCs intravenously (3×106 cells) after the last dose of DENPs and Group IV (MSCs-MVs group) received MSCs-MVs (0.5 mg/mL) intravenously after the last dose of DENPs. Lung tissue were subjected to histological and immunohistochemical assessment. Inflammatory cytokines and bronchoalveolar lavage fluid (BALF) contents of inflammatory cells, albumin, LDH and total proteins were evaluated. Results: Histological picture of lung tissue in DENPs group showed numerous collapsed alveoli, thick interalveolar septa and marked cellular infiltration. Elastic fibers were markedly decreased by DENPs. Increased optical density of NF-κB/p65 immunoreactivity. Bronchoalveolar lavage fluid showed significant elevation of inflammatory cytokines (TNF-a, IL-6), polymorphonuclear leukocytes (PMN), neutrophils, macrophages, LDH, total proteins and albumin. Treatment with either MSCs or MSCs-MVs led to a significant amelioration of all of the aforementioned studied parameters. Conclusion: MSCs-MVs and MSCs showed significant therapeutic effects against DENPs damaging effects on the lung tissues via their regenerative capacity and anti-inflammatory effects.

Conversion of renewable substrates for biosurfactant production by Rhizopus arrhizus UCP 1607 and enhancing the removal of diesel oil from marine soil

BACKGROUND: The use of agro-industrial wastes to produce high value-added biomolecules such as biosurfactants is a promising approach for lowering the total costs of production. This study aimed to produce biosurfactants using Rhizopus arrhizus UCP 1607, with crude glycerol (CG) and corn steep liquor (CSL) as substrates. In addition, the biomolecule was characterized, and its efficiency in removing petroderivatives from marine soil was investigated. RESULTS: A 22 factorial design was applied, and the best condition for producing the biosurfactant was determined in assay 4 (3% CG and 5% CSL). The biosurfactant reduced the surface tension of water from 72 to 28.8 mN/m and produced a yield of 1.74 g/L. The preliminary biochemical characterization showed that the biosurfactant consisted of proteins (38.0%), carbohydrates (35.4%), and lipids (5.5%). The compounds presented an anionic character, nontoxicity, and great stability for all conditions tested. The biomolecule displayed great ability in dispersing hydrophobic substrates in water, thereby resulting in 53.4 cm2 ODA. The best efficiency of the biosurfactant in removing the pollutant diesel oil from marine soil was 79.4%. CONCLUSIONS: This study demonstrated the ability of R. arrhizus UCP1607 to produce a low-cost biosurfactant characterized as a glycoprotein and its potential use in the bioremediation of the hydrophobic diesel oil pollutant in marine soil

Analysis for Streptomyces spp. recovered from oil refinery soils to grow on diesel

Aims@#The investigation aimed to examine the crude oil-contaminated soil Streptomyces flora and study their capability to grow on diesel fuel as a sole carbon source and their analysis for the presence of alkane hydroxylase gene (alkB) by PCR. @*Methodology and results@#A total of 17 Streptomyces isolates were recovered from hydrocarbon-contaminated soil samples on starch casein nitrate agar medium with the ability of 4 isolates to grow on diesel [0.1 % (v/v)] as assessed by agar plate diffusion method, enzymatic assay and dry weight measurements. The ability of the four isolates (JR2b, JR3a, JR5b, and JR6f) to grow on diesel was revealed by the colour change of the reaction mixture and showing a growth response by growing around diesel-containing wells with a percentage increase in the dry weight of 24.60, 26.23, 18.03, and 18.03 after 28 days of incubation as compared to zero time, respectively. Although the four isolates were capable to degrade diesel as indicated by the three assessment techniques, they did not show any PCR product. @*Conclusion, significance and impact of study@#The isolates that grew on diesel and showed no PCR product might not contain the alkB gene, which implies that alkB gene is not the only gene that is responsible for the degradation of alkanes.

Hydrocarbon pneumonitis following fuel siphonage: A case report and literature review / 世界急诊医学杂志（英文）

BACKGROUND@# People sometimes siphon fuel to fill their tanks. However, this is a potentially dangerous procedure and may cause hydrocarbon pneumonitis. We present the case of a patient with severe hydrocarbon pneumonitis after siphoning fuel. The patient underwent artificial ventilation and was admitted to hospital for 97 days.@*METHODS@# We review the relevant literature for a better understanding of clinical features and management strategies for hydrocarbon pneumonitis following fuel siphonage.@*RESULTS@# We reviewed 15 articles, which included 3 original articles and 12 case reports that reported the clinical features of fuel siphonage. In addition, we added our presented case for data analysis. A total of 40 cases were included in this review. The literature review found that hydrocarbon pneumonitis caused by fuel siphonage occurs worldwide and that most patients (80%) became symptomatic within 1 day of aspiration. Cough (70%), chest pain (62.5%), dyspnoea (55%), and fever (52.5%) presented in more than half of all patients. The right middle lobe (80%) was the predominantly involved lung field; more than one-third of patients (36.7%) showed the involvement of two lobes.@*CONCLUSION@# Patient history, computed tomographic scans of the chest, and bronchoalveolar lavage are the commonly used diagnostic tools. Supportive care remains the foundation of treatment, whereas antibiotics, steroids, and bronchoalveolar lavage are practical therapies. Patients' clinical improvement precedes the resolution of lesions on chest X-ray. Most complications arise from pulmonary lesions. The prognosis of patients suffering from hydrocarbon pneumonitis following fuel siphonage might be improved by accurate diagnosis and appropriate care.

Workplace Diesel Exhausts and Gasoline Exposure and Risk of Colorectal Cancer in Four Nordic Countries

BACKGROUND: Evidence on associations between occupational diesel exhaust and gasoline exposure and colorectal cancer is limited. We aimed to assess the effect of workplace exposure to diesel exhaust and gasoline on the risk of colorectal cancer. METHODS: This caseecontrol study included 181,709 colon cancer and 109,227 rectal cancer cases diagnosed between 1961 and 2005 in Finland, Iceland, Norway, and Sweden. Cases and controls were identified from the Nordic Occupational Cancer Study cohort and matched for country, birth year, and sex. Diesel exhaust and gasoline exposure values were assigned by country-specific job-exposure matrices. Odds ratios and 95% confidence intervals were calculated by using conditional logistic regression models. The results were adjusted for physical strain at work and occupational exposure to benzene, formaldehyde, ionizing radiation, chlorinated hydrocarbons, chromium, and wood dust. RESULTS: Diesel exhaust exposure was associated with a small increase in the risk of rectal cancer (odds ratio 1/4 1.05, 95% confidence interval 1.02–1.08). Gasoline exposure was not associated with colorectal cancer risk. CONCLUSION: This study showed a small risk increase for rectal cancer after workplace diesel exhaust exposure. However, this finding could be due to chance, given the limitations of the study.

Adsorción de diésel en solución acuosa sobre aserrín cedro (cedrela odorata l) en columna de lecho fijo

Se evaluó el uso de aserrín de Cedro (Cedrela odorata L.) en la adsorción de diésel en solución acuosa. El potencial del aserrín como adsorbente en sistema continuo fue investigado, variando la cantidad de biomasa y el caudal, usando columnas de plástico transparente de diámetro 3,5 cm y una altura de 18,5 cm, con tiempo de contacto de 180 min, tomando alícuotas de 50 mL en diferentes intervalos. La medición de la concentración residual fue realizada por cromatografía de gases, donde se estableció la saturación de la columna a las mejores condiciones; se determinó que a los 600 minutos se llega a un equilibrio, en el cual posiblemente se produce una alta saturación de la biomasa, que alcanza una capacidad de 62,93mg/g. Esta fue determinada con el modelo de Thomas a un flujo de 0,1 mL/s y 4 g de aserrín de cedro.

The use of Cedar sawdust (Cedrela odorata L.) in the adsorption of diesel in aqueous solution was evaluated. Sawdust adsorbent potential in continuous system was analyzed, varying the amount of biomass and the flow rate, using transparent plastic columns of diameter 3.5 cm and 18.5 cm height, with a contact time of 180 min, taking aliquots of 50 mL in different intervals; the measurement of residual concentration was made through gas chromatography, finally, saturation of the column at the best conditions was established. Determining that at 600 minutes balance is reached, in which a high saturation of the biomass possibly occurs, reaching a capacity of 62.93mg / g determined with the Thomas model at a flow of 0.1 mL / s. 4 g of cedar sawdust.

Avaliou-se o uso de serragem de cedro (Cedrela odorata L.) na ad-sorção de diesel em solução aquosa. O potencial da serragem como adsorvente em um sistema contínuo foi investigado através da variação da quantidade de biomassa e a taxa de fluxo, utilizando colunas de plástico transparente de diâmetro de 3,5 cm e uma altura de 18,5 cm, com o tempo de contato de 180 minutos, tendo alíquotas de 50 mL em diferentes intervalos; a medição da concentração residual foi feita por cromatografia gasosa; finalmente, a saturação da coluna foi estabelecida nas melhores condições. Determinou-se que aos 600 minutos é alcançado um equilíbrio, no qual possivelmente ocorre uma alta saturação da biomassa, atingindo uma capacidade de 62,93mg / g, determinada com o modelo de Thomas a um fluxo de 0,1 mL / s. 4 g de serradura de cedro.

Biosurfactants produced by Microbacterium sp, isolated from aquatic macrophytes in hydrocarbon-contaminated area in the Rio Negro, Manaus, Amazonas / Biossurfactantes produzidos por Microbacterium sp, isolada de macrófita aquática em área impactada por hidrocarbonetos no rio Negro, Manaus, Amazonas

Endophytic bacteria isolated from Eichhornia crassipes (Mart) Solms., collected in oil contaminated wastewater of effluent generated by Petrobras refinery in Manaus were investigated to determine their potential for producing biosurfactants. Assay with 2.6-dichlorophenol indophenol (DCPIP) indicator to verify hydrocarbon biodegradation activity; oil emulsification test; drop-collapse method; surface tension and growth curve of biosurfactant production. The M87 Microbacterium sp. strain chosen for this work was identified by the sequencing of the rDNA region and the chemical characterization was performed by FTIR, UFLC/MS and 1H RMN techniques. The selected bacterial isolate provided 3g L-1 of biosurfactant, using diesel oil as sole carbon source, being efficient in biodegrading oil as demonstrated by the DCPIP test. Fractions obtained by column chromatography were efficient in reducing water surface tension around 40 mN m-1, especially fraction 1, which reduced it to 34.17 mN m-1. The different techniques of chemical analysis used for the identification of the biosurfactant isolate indicated that this is probably a long - chain fatty acid lipid type, which may be used in the future as both biosurfactant in decontamination processes of hydrocarbon-polluted areas or as bioemulsifier in countless processes, since it exhibited no toxicity as determined by Alamar Blue assay.

Foram investigadas bactérias endofíticas isoladas de Eichhornia crassipes (Mart.) Solms., coletadas em águas contaminadas com resíduos de petróleo em um afluente da refinaria da Petrobrás/Manaus, para avaliação da produção de biossurfactantes. Para selecionar o micro-organismos à produção e caracterização de biossurfactantes, foram realizados os seguintes testes: a descoloração do indicador 2,6 indofenol (DCPIP), emulsificação do diesel, colapso da gota, tensão superficial e curva de produção. A caracterização química foi realizada por meio das técnicas de FT-IR, UFLC/MS e RMN1H. A bactéria M87 Microbacterium neste estudo, foi identificada pelo sequenciamento da região rDNA e produziu 3g L-1 de biossurfactantes utilizando o diesel como fonte de carbono, mostrando-se eficiente na ação biodegradadora do petróleo, por meio do teste de Indofenol (DCPIP). As frações obtidas, mostraram-se eficazes na redução da tensão superficial da água abaixo de 40 mN m-1, com destaque para a fração 1 que reduziu a tensão superficial para 34,17 mN m-1. Pelas análises química utilizadas, pode-se inferir que, provavelmente, se trata de um ácido graxo de cadeia longa, que pode ser utilizado futuramente tanto como biossurfactante em processos de descontaminação de ambientes impactados por hidrocarbonetos, assim como bioemulsificante em inúmeros processos uma vez que não apresentou toxicidade por meio do teste realizado.

Siphoning diesel: a fatal mistake

Diesel is commonly used as fuel for engines and is distilled from petroleum. Diesel has toxic potential and can affect multiple organs. Exposure can occur after ingestion, inhalation or through the dermal route. The practice of siphoning diesel using a rubber tubing and the mouth is common in rural communities. This can lead to accidental ingestion and aspiration. Here we report a case of a patient who accidentally ingested diesel during siphoning, which caused extensive erosion of the oral cavity and oesophagus leading to pneumomediastinum and severe chemical lung injury. The patient responded well initially to steroids and supportive care but required prolonged hospitalisation. He developed complications of nosocomial infection and succumbed 23 days after admission.

Association of etheno-DNA adduct and DNA methylation level among workers exposed to diesel engine exhaust / 中华预防医学杂志

Objective@#To investigate the association between etheno-DNA adduct and the promoter of DNA methylation levels of cyclin dependent kinase inhibitor 2A (P16), Ras association domain family 1 (RASSF1A) and O-6-methylguanine-DNA methyltransferase (MGMT) in workers with occupational exposure to diesel engine exhaust (DEE).@*Methods@#We recruited 124 diesel engine testing workers as DEE exposure group and 112 water pump operator in the same area as control group in Henan province in 2012 using cluster sampling. The demographic data were obtained by questionnaire survey; urine after work and venous blood samples were collected from each subject. The urinary etheno-DNA adducts were detected using UPLC-MS/MS, including 1,N6-etheno-2'-deoxyadenosine (εdA) and 3,N4-etheno-2'-deoxycytidine(εdC). The DNA methylation levels of P16, RASSF1A, and MGMT were evaluated using bisulfite-pyrosequencing assay. The percentage of methylation was expressed as the 5-methylcytosine (5mC) over the sum of cytosines (%5mC). Spearman correlation and multiple linear regression were applied to analyze the association between etheno-DNA adducts and DNA methylation of P16, RASSF1A, and MGMT.@*Results@#The median (P25-P75) of urinary εdA level was 230.00 (98.04-470.91) pmol/g creatinine in DEE exposure group, and 102.10 (49.95-194.48) creatinine in control group. The level of εdA was higher in DEE exposure group than control group (P<0.001). DNA methylation levels of P16, RASSF1A and MGMT were 2.04±0.41, 2.19 (1.94-2.51), 2.22 (1.94-2.46)%5mC in exposure group, and 2.19±0.40, 2.41 (2.11-2.67), 2.44 (2.15-2.91)%5mC in control group. DNA methylation levels were lower in exposure group (P values were 0.005, 0.002 and 0.001, respectively). Spearman correlation analysis showed that DNA methylation levels of P16, RASSF1A, and MGMT were negative associated with urinary εdA level (r values were -0.155, -0.137, and -0.198, respectively, P<0.05). No significant correlation was observed between the εdC level and any measured DNA methylation levels (P>0.05) . Multiple linear regression confirmed the negative correlation between εdA and DNA methylation levels of P16, RASSF1A, and MGMT in non-smoking group (β (95%CI) was -0.068 (-0.132--0.003), -0.082 (-0.159--0.004) and -0.048 (-0.090--0.007), P values were 0.039, 0.039 and 0.024, respectively). Moreover, εdC was negative associated with DNA methylation level of MGMT in non-smoking group (β (95%CI) was -0.094 (-0.179--0.008), P=0.032).@*Conclusion@#DEE exposure could induce the increased of εdA and decreased of DNA methylation levels of P16, RASSF1A and MGMT.

Isolation and characterization of hydrocarbon-degrading bacteria from gas station leaking-contaminated groundwater in the Southern Amazon, Brazil

Abstract Twenty-three hydrocarbon-degrading bacteria strains were isolated from gas station leaking-contaminated groundwater located in the Southern Amazon, Brazil. Based on hydrocarbon (diesel, hexadecane, benzene, toluene and xylene) degradation ability, two strains were selected for further study. The amplification and sequencing of the 16S rRNA gene showed that these two strains belonged to the genus Bacillus (Bacillus sp. L26 and Bacillus sp. L30). GC-MS analysis showed that strain L30 was the most effective in degrading n-alkane (C10-C27) from diesel after 7 days of cultivation in mineral medium. Both strains produced biosurfactants and showed emulsification activity, specially the strain L30. Alkane hydroxylase gene (group III), which is important for alkane biodegradation, was present in strains. As a result, this study indicated that these bacteria could have promising applications in hydrocarbon bioremediation.

Resumo Vinte e três linhagens bacterianas degradadoras de hidrocarbonetos foram isoladas de água subterrânea contaminada por vazamento em posto de combustível no sul da Amazônia, Brasil. Com base na habilidade de degradar hidrocarbonetos (diesel, hexadecano, benzeno, tolueno e xileno), duas linhagens foram selecionadas para estudos posteriores. A amplificação e sequenciamento do gene 16S rRNA demonstrou que essas linhagens pertencem ao gênero Bacillus (Bacillus sp. L26 and Bacillus sp. L30). Análises de GC-MS mostraram que a linhagem L30 foi mais eficiente em degradar n-alcanos (C10-C27) presentes no diesel, após 7 dias de cultivo em meio mineral. Ambas as linhagens produziram biossurfactantes e apresentaram atividade emulsificante, especialmente a linhagem L30. O gene alcano hidroxilase (grupo III), o qual é importante para degradação de alcanos, foram detectados nas linhagens. Como resultado, este estudo indicou que essas linhagens bacterianas podem ser promissoras se aplicadas em processos de biorremediação.