Polyaromatic Hydrocarbon Degradation of Moss Endophytic Fungi Isolated from Macromitrium sp. in Sri Lanka

Polyaromatic hydrocarbons （PAHs）, which are the major by-products of fossil fuel burning, are released to the environment with the immense growth of urbanization and industrialization. These pollutants are subsequently deposited on many substrates including plant surfaces. Due to their toxicity, mutagenicity, carcinogenicity and recalcitrant nature, they can result in many hazardous effects on human health. Application of endophytes in bioremediation has shown much promise in removing these PAHs from contaminated substrates. In the present study, an attempt was made to isolate and identify endophytic fungi from the moss plant Macromitrium sp. （frequently available） in Sapugaskanda （highly polluted） and HettimuUa （less polluted） areas in Sri Lanka. Subsequently, their potential in degrading PAHs （naphthalene and phenanthrene） was investigated. Endophytes from the moss were isolated following the surface sterilization method, and their physiological roles in degrading naphthalene and phenanthrene were carried out using plate assays, spectrophotometric and high-performance liquid chromatography （HPLC） analysis. Most of the endophytie fungi isolated from Macromitrium sp. were able to grow in Bacto Bushnell-Haas （BBH） medium incorporated with naphthalene and phenanthrene, separately, displaying colony diameters more than 30 mm. As per the results obtained from spectrophotometric and HPLC analysis, Penicillium oxalicum, Nigrospora oryzae, Aspergillus oryzae, A. aculeatus, Penicillium sp.1, Penicillium sp.5, Eupenicillium sp.2 and Mortierella sp.1 degraded both naphthalene and phenanthrene more than 85%. The fmdings of the present investigation provide some insight into how these endophytic fungi could be used for bioremediation of PAHs in environmental sites where contamination prevails, and also open avenues for future research in the relevant field.

Identification, Quantification and <i>In-Vitro</i>Genotoxicity of Major Polyaromatic Hydrocarbons Produced by Sugarcane Fly Ash Emitted from Sugarmill

Sugarcane burning during harvest and non-harvest season emits various pollutants like volatile organic compounds (VOCs), alkanes, and PAHs (Polyaromatic hydrocarbons) in the surrounding environment. Among these pollutants, PAHs are of uttermost concern due to their high level of toxicity. Burning of sugarcane bagase in sugar mill results in the production of fly ash. Fly ash is produced as a result of sugarcane bagasse burning in sugar mills. In present study, fly ash that comes out from the sugar mill chimney was collected from Western Uttar Pradesh, India and used for further analysis. High temperature and incomplete combustion inside chimney lead to the formation of PAHs. Extraction of PAHs present in fly ash samples was done by ultrasonication method and was identified with GC-FID (gas chromatography-flame ionization detector). Results exhibit the presence of eight PAHs in fly ash samples where the Benzo(a)pyrene and Naphthalene were found to be in high concentration. Furthermore, we have evaluated toxic effects of fly ash and Polyaromatic hydrocarbons (Standard of BaP & Nap) through different methods i.e. MTT, ROS and comet assay. Significant reduction (p < 0.001) in cell viability was noted in cells treated with fly ash as compared to control. Fly ash samples were also found to induce significant oxidative stress in HeLa cells, which ultimately causes DNA damage. Therefore, it may be concluded that the fly ash samples are toxic to the environment due to the presence of PAHs. Hence, the present study plays an important role in determining the harmful effects of PAHs and their source of occurrence.

A newly defined dioxygenase system from Mycobacterium vanbaalenii PYR-1 endowed with an enhanced activity of dihydroxylation of high-molecular-weight polyaromatic hydrocarbons

NidA3B3 is a terminal dioxygenase whose favorable substrates are high-molecular-weight polyaromatic hydrocarbons(PAHs)from Mycobacterium vanbaalenii PYR-1,a powerftil PAHs degradation strain.NidA3B3 was reported to incorporate a dioxygen into the benzene ring of PAHs when equipped with an exogenous electron transport chain components PhdCD from Nocarciioides sp.strain KP7 by biotransformation,but this enzyme system was not particularly efficient.In this study,strain PYR-1 was confirmed to utilize four different PAHs at different growth rates.When PhtAcAd,an endogenous electron transport chain of a phthalate dioxygenase system,was substituted for PhdCD to couple with NidA3B3,the specific activity to convert phenanthrene by strain BL21(DE3)[pNidA3B3-PhAcAd]was 0.15±0.03 U/mg,but the specific activity of strain BL21(DE3)[pNidA3B3-PhdCD]was only 0.025±0.006U/mg.In addition,FNidA3,encoded by a newly defined ORF,has a prolonged 19-amino acid sequence at the N-terminus compared with NidA3.FNidA3B3 increased the activity by 50%approximately than NidA3B3 when using PhtAcAd.Components of the electron transport chain PhtAc and PhtAd were purified and characterized.The Km,kcal,kcat/Km values of the PhtAd were 123±26.9 pM,503±49.9 min^-1,4.1μM^-1·min^-1,respectively.And the,Km,Kcat,Kcat/Km values of the ferredoxin PhtAc were (52.5±9.7)μM,3.8±0.19min^-1 and 0.07μM^-1 min1,respectively.Basing on the phylogenetic analysis,NidA3/FNidA3 were far from its isoenzyme NidA from the same strain.Combining their primary differences of transcriptional pattern in vivo,it indicated that the functionally similar Rieske dioxygenases NidA3B3/FNidA3B3 and NidAB might originate from different ancestors.

Three-dimensional conjugated macrocycle with large polyaromatic blocks constructed by post-π-extension

Generally,the conjugated homo-macrocycles(CHMs)are synthesized by covalently linking the repeating subunits.However,large subunits are often difficult to conjugate together due to severe stereo-hindrance.Meanwhile,large polyaromatic blocks can not only incorporate its appealing electronic and optical properties into CHMs but also distort the CHMs from planar to three-dimensional(3D)molecular structure.Here we synthesized the 3D CHM composed of large polyaromatic units by post-π-extension.Specifically,cyclo-m-phenylenes,as the cyclic precursor,wereπ-extended by C-C coupling and then subjected to dehydrocyclization,affording cyclo-1,3-dibenzo[e,l]pyrenylenes(CMDP).The structures of CMDPs were unambiguously characterized by single crystal X-ray diffraction,showing a congested and strained 3D conformation,which was also confirmed by theoretical calculations.Compared with the monomer,CMDPs showed redshifted absorption and emission,as well as a ten-fold enhancement in photoluminescence quantum yield,which could be attributed to their 3D conformation.

Charge Transfer and Bonding Strength in Lithium-intercalated Polyaromatic Hydrocarbons Studied by Photoelectron Spectroscopy

1 Results The potential applications of small-, medium-and large-size polyaromatic hydrocarbons for charge and energy storage in lithium metal and lithium ion batteries are discussed. In order to find the best carbon-based electrode materials, the specific roles of the molecular and solid-state contributions have to be understood. For the molecular contributions, a semi-quantitative method is proposed to compare the charge storage capability of polyaromatic hydrocarbon molecules. A compilation of result...

Environmental pollution and diabetes mellitus

Diabetes mellitus(DM)is a chromic metabolic disease that affects a large segment of the population worldwide.Physical inactivity,poor nutrition,and genetic predisposition are main risk factors for disease development.In the last decade,it was clear to the scientific community that DM development is linked to a novel disease inducer that was later defined as diabetogenic factors of pollution and endocrine disrupting agents.Environmental pollution is exponentially increasing in uncontrolled manner in several countries.Environmental pollutants are of diverse nature and toxicities,including polyaromatic hydrocarbons(PAHs),pesticides,and heavy metals.In the current review,we shed light on the impact of each class of these pollutants and the underlined molecular mechanism of diabetes induction and biological toxicities.Finally,a brief overview about the connection between coronavirus disease 2019 and diabetes pandemics is presented.

An evaluation of the emission profile for two-wheelers at a traffic junction

Two-wheeler vehicles are an important mode of transportation in developing countries. However, the emissions from two-wheeler vehicles are significant. Urban two-wheeler vehicles with gasoline-fueled engines produce NOx and particulate matter emissions that affect urban air quality. During traffic light stops and programmed stops, for instance, pollutants are emitted and are dangerous to human health. In this experimental study, two-wheeler vehicles with different makes, technologies and engine capacities were tested for exhaust emissions including gravimetric and online measurements at different engine speeds and a no load condition at a simulated traffic junction. Gravimetric measurements were performed by collecting the particulate mass （at two engine speeds： 1500 and 2500 rpm） from a diluted engine-out exhaust on quartz filter paper. Next, these collected particulates were used to determine the presence of metals, as well as the benzene soluble organic fraction （BSOF）. The total particulate mass, BSOF and trace elements were slightly higher at a higher engine speed （2500 rpm）. Online measurements were performed by sampling the engine exhaust （at four engine speeds： 1500, 2000, 2500, and 3000rpm） and using online instruments to determine the particle number and size distribution, the particle-bound polyaromatic hydrocarbons （PAHs）, the gaseous emissions and the smoke opacity. Engines with higher cubic capacity emitted a higher concentration of nano-particles. The particle-bound PAH concentration increased as the engine speed increased, but this concentration was notably low for the highest engine speed tested （3000 rpm）. The regulated gaseous emissions increased as the engine speed increased for all vehicles.