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Respiratory Medicine May 2017The human race has been exposed to the potential toxicity of hydrocarbons, whether by the inhaled or ingested route, for thousands of years and the consequent... (Review)
Review
The human race has been exposed to the potential toxicity of hydrocarbons, whether by the inhaled or ingested route, for thousands of years and the consequent inflammatory reaction in the lungs depends on the degree of exposure, volatility and viscosity of the particular hydrocarbon in question. Heating, lighting, transportation, industry and nature all provide the potential for both inhalation and/or ingestion of hydrocarbons. Some forms, such as those related to petroleum products, e.g. diesel exhaust particles (DEP) and polycyclic aromatic hydrocarbons (PAH) have been shown to cause both malignant and non-malignant respiratory diseases. Accidental ingestion represents another significant exposure risk and we now have increasing evidence that pollutant particles may adsorb allergens to their surface and potentially enhance the allergic response. It seems unlikely that this potential will significantly decrease in the near future and depending on individual socio-economic circumstances, work environment and habitation, the risks of significant lung disease will vary. This review outlines the domestic, outdoor, occupational and natural sources of hydrocarbon exposure and considers the evidence relating to radiological and pathological lung changes in both animals and man. The acute effects of hydrocarbon toxicity are well recognised but the effects of longer term, lower exposure, and the mechanisms of their toxicity, require further research.
Topics: Adult; Air Pollutants; Animals; Environmental Exposure; Female; Humans; Hydrocarbons; Inhalation Exposure; Lung; Lung Diseases; Male; Middle Aged; Occupational Exposure; Particulate Matter; Polycyclic Aromatic Hydrocarbons; Social Class; Vehicle Emissions
PubMed: 28427549
DOI: 10.1016/j.rmed.2017.03.021 -
The Protein Journal Feb 2018Antimicrobial peptides are promising candidates for anti-infective pharmaceuticals. Unfortunately, because of their low proteolytic and chemical stability, their usage... (Review)
Review
Antimicrobial peptides are promising candidates for anti-infective pharmaceuticals. Unfortunately, because of their low proteolytic and chemical stability, their usage is generally narrowed down to topical formulations. Until now, numerous approaches to increase peptide stability have been proposed. One of them, peptide hydrocarbon stapling, a modification based on stabilizing peptide secondary structure with a side-chain covalent hydrocarbon bridge, have been successfully applied to many peptides. Moreover, constraining secondary structure of peptides have also been proven to increase their biological activity. This review article describes studies on hydrocarbon stapled antimicrobial peptides with respect to improved drug-like properties.
Topics: Animals; Anti-Bacterial Agents; Antimicrobial Cationic Peptides; Cross-Linking Reagents; Humans; Hydrocarbons
PubMed: 29330644
DOI: 10.1007/s10930-018-9755-0 -
International Journal of Environmental... Nov 2022To improve the environmental sustainability of cleanup activities of contaminated sites there is a need to develop technologies that minimize soil and habitat...
To improve the environmental sustainability of cleanup activities of contaminated sites there is a need to develop technologies that minimize soil and habitat disturbances. Cleanup technologies, such as bioremediation, are based on biological products and processes, and they are important for the future of our planet. We studied the potential of γ-poly glutamic acid (PGA) as a natural component of biofilm produced by sp. to be used for the decomposition of petroleum products, such as heavy naphtha (N), lubricating oil (O), and grease (G). The study aimed to assess the impact of the use of different concentrations of PGA on the degradation process of various fractions of petroleum hydrocarbons (PH) and its effect on bacterial population growth in harsh conditions of PH contamination. In laboratory conditions, four treatments of PGA with each of the petroleum products (N, O, and G) were tested: PGA (reference), PGA (1% PGA), PGA (1% PGA with ), and PGA (10% PGA). After 7, 28, 56, and 112 days of the experiment, the percentage yield extraction, hydrocarbon mass loss, geochemical ratios, pH, electrical conductivity, and microorganisms survival were determined. We observed an increase in PH removal, reflected as a higher amount of extraction yield (growing with time and reaching about 11% in G) and loss of hydrocarbon mass (about 4% in O and G) in all treatments of the PGA compared to the reference. The positive degradation impact was intensive until around day 60. The PH removal stimulation by PGA was also reflected by changes in the values of geochemical ratios, which indicated that the highest rate of degradation was at the initial stage of the process. In general, for the stimulation of PH removal, using a lower (1%) concentration of PGA resulted in better performance than a higher concentration (10%). The PH removal facilitated by PGA is related to the anionic homopoliamid structure of the molecule and its action as a surfactant, which leads to the formation of micelles and the gradual release of PH absorbed in the zeolite carrier. Moreover, the protective properties of PGA against the extinction of bacteria under high concentrations of PH were identified. Generally, the γ-PGA biopolymer helps to degrade the hydrocarbon pollutants and stabilize the environment suitable for microbial degraders development.
Topics: Hydrocarbons; Petroleum; Polyglutamic Acid
PubMed: 36429785
DOI: 10.3390/ijerph192215066 -
Cell Mar 2018Hydrocarbon-degrading bacteria are phylogenetically and physiologically diverse and employ layered strategies to sense hydrocarbons, respond transcriptionally, and then...
Hydrocarbon-degrading bacteria are phylogenetically and physiologically diverse and employ layered strategies to sense hydrocarbons, respond transcriptionally, and then move toward an oil source. They then produce biopolymers that increase hydrocarbon bioavailability. This SnapShot highlights how these bacteria respond to and then remove hydrocarbon contaminants from the environment. To view this SnapShot, open or download the PDF.
Topics: Bacteria; Biodegradation, Environmental; Cell Membrane; Hydrocarbons; Hydrophobic and Hydrophilic Interactions; Metabolic Networks and Pathways; Models, Biological; Quorum Sensing; Soil Microbiology; Surface-Active Agents; Water Microbiology
PubMed: 29522751
DOI: 10.1016/j.cell.2018.02.059 -
Archaea (Vancouver, B.C.) 2018Bioremediation is the use of microorganisms for the degradation or removal of contaminants. Most bioremediation research has focused on processes performed by the domain... (Review)
Review
Bioremediation is the use of microorganisms for the degradation or removal of contaminants. Most bioremediation research has focused on processes performed by the domain ; however, are known to play important roles in many situations. In extreme conditions, such as halophilic or acidophilic environments, are well suited for bioremediation. In other conditions, collaboratively work alongside during biodegradation. In this review, the various roles that have in bioremediation is covered, including halophilic hydrocarbon degradation, acidophilic hydrocarbon degradation, hydrocarbon degradation in nonextreme environments such as soils and oceans, metal remediation, acid mine drainage, and dehalogenation. Research needs are addressed in these areas. Beyond bioremediation, these processes are important for wastewater treatment (particularly industrial wastewater treatment) and help in the understanding of the natural microbial ecology of several genera.
Topics: Archaea; Biodegradation, Environmental; Environmental Pollutants; Hydrocarbons
PubMed: 30254509
DOI: 10.1155/2018/3194108 -
Ecotoxicology and Environmental Safety Aug 2022Fungal laccase (Lac) has become a very useful biocatalyst in different industries, bio-refineries and, most importantly, bioremediation. Many reports have also linked...
Fungal laccase (Lac) has become a very useful biocatalyst in different industries, bio-refineries and, most importantly, bioremediation. Many reports have also linked hydrocarbon tolerance and degradation by various microorganisms with Lac secretion. In this study, Trametes trogii Lac (Ttlcc1) was engineered into Saccharomyces cerevisiae strain CEN.PK2-1 C under the constitutive GPD promoter (pGPD) for multi-fold synthesis with efficient hydrocarbon tolerance and degradation. Protein expression in heterologous hosts is strictly strain-specific, it can also be influenced by the synthetic design and culture conditions. We compared synthetic designs with different shuttle vectors for the yeast strains and investigated the best culture conditions by varying the pH, temperature, carbon, nitrogen sources, and CuSO amount. Two S. cerevisiae strains were built in this study: byMM935 and byMM938. They carry the transcription unit pGPD-Ttlcc1-CYC1t either inside the pRSII406 integrative plasmid (byMM935) or the pRSII426 multicopy plasmid (byMM938). The performance of these two synthetic strains were studied by comparing them to the wild-type strain (byMM584). Both byMM935 and byMM938 showed significant response to different carbon sources (glucose, galactose, lactose, maltose, and sucrose), nitrogen sources (NHCl, NHNO, KNO, malt extract, peptone, and yeast extract), and solid state fermentation of different plant biomasses (bagasse, banana peels, corn cob, mandarin peels, and peanut shells). They performed best in optimized growth conditions with specific carbon and nitrogen sources, and a preferred pH in the range 3.5-4.5, temperature between 30 and 40 C, and 1 mM CuSO In optimized yeast-growth medium, strain byMM935 showed the highest laccase activities of 1.621 ± 0.063 U/mL at 64 h, whereas byMM938 gave its highest activity (1.417 ± 0.055 U/mL) at 48 h. In this work, we established, by using Bushnell Hass synthetic medium, that the new Ttlcc1-yeast strains tolerated extreme pH and complex hydrocarbon mixture (CHM) toxicity. They degraded 60-90% of the key components in CHM within 48 h, including poly-cyclic aromatic hydrocarbons, alkyl indenes, alkyl tetralines, alkyl benzenes, alkyl biphenyls, and BTEX (Benzene, Toluene, Ethylbenzene, and Xylenes). This is the first report on the hydrocarbon degradation potential of a Ttlcc1-yeast. Compared to the native organism, such synthetic strains are better suited for meeting growing demands and have potentials for application in large-scale in situ bioremediation of hydrocarbon-polluted sites.
Topics: Benzene; Carbon; Culture Media; Environmental Pollutants; Hydrocarbons; Laccase; Nitrogen; Saccharomyces cerevisiae; Trametes
PubMed: 35724516
DOI: 10.1016/j.ecoenv.2022.113768 -
Chemistry (Weinheim An Der Bergstrasse,... Nov 2022The "metathesis reaction" is a straightforward and often metal-catalyzed chemical reaction that transforms two hydrocarbon molecules to two new hydrocarbons by exchange... (Review)
Review
The "metathesis reaction" is a straightforward and often metal-catalyzed chemical reaction that transforms two hydrocarbon molecules to two new hydrocarbons by exchange of molecular fragments. Alkane, alkene and alkyne metathesis have become an important tool in synthetic chemistry and have provided access to complex organic structures. Since the discovery of industrial olefin metathesis in the 1960s, many modifications have been reported; thus, increasing scope and improving reaction selectivity. Olefin metathesis catalysts based on high-valent group six elements or Ru(IV) have been developed and improved through ligand modifications. In addition, significant effort was invested to realize olefin metathesis with a non-toxic, bio-compatible and one of the most abundant elements in the earth's crust; namely, iron. First evidences suggest that low-valent Fe(II) complexes are active in olefin metathesis. Although the latter has not been unambiguously established, this review summarizes the key advances in the field and aims to guide through the challenges.
Topics: Alkenes; Iron; Catalysis; Hydrocarbons; Ligands
PubMed: 35770829
DOI: 10.1002/chem.202201414 -
Molecules (Basel, Switzerland) Feb 2020Concerns about depleting fossil fuels and global warming effects are pushing our society to search for new renewable sources of energy with the potential to substitute... (Review)
Review
Concerns about depleting fossil fuels and global warming effects are pushing our society to search for new renewable sources of energy with the potential to substitute coal, natural gas, and petroleum. In this sense, biomass, the only renewable source of carbon available on Earth, is the perfect replacement for petroleum in producing renewable fuels. The aviation sector is responsible for a significant fraction of greenhouse gas emissions, and two billion barrels of petroleum are being consumed annually to produce the jet fuels required to transport people and goods around the world. Governments are pushing directives to replace fossil fuel-derived jet fuels with those derived from biomass. The present mini review is aimed to summarize the main technologies available today for converting biomass into liquid hydrocarbon fuels with a molecular weight and structure suitable for being used as aviation fuels. Particular emphasis will be placed on those routes involving heterogeneous catalysts.
Topics: Biofuels; Biomass; Catalysis; Humans; Hydrocarbons; Natural Gas
PubMed: 32059552
DOI: 10.3390/molecules25040802 -
Molecules (Basel, Switzerland) Sep 2019Petroleum hydrocarbons represent the most frequent environmental contaminant. The introduction of petroleum hydrocarbons into a pristine environment immediately changes... (Review)
Review
Petroleum hydrocarbons represent the most frequent environmental contaminant. The introduction of petroleum hydrocarbons into a pristine environment immediately changes the nature of that environment, resulting in reduced ecosystem functionality. Natural attenuation represents the single, most important biological process which removes petroleum hydrocarbons from the environment. It is a process where microorganisms present at the site degrade the organic contaminants without the input of external bioremediation enhancers (i.e., electron donors, electron acceptors, other microorganisms or nutrients). So successful is this natural attenuation process that in environmental biotechnology, bioremediation has developed steadily over the past 50 years based on this natural biodegradation process. Bioremediation is recognized as the most environmentally friendly remediation approach for the removal of petroleum hydrocarbons from an environment as it does not require intensive chemical, mechanical, and costly interventions. However, it is under-utilized as a commercial remediation strategy due to incomplete hydrocarbon catabolism and lengthy remediation times when compared with rival technologies. This review aims to describe the fate of petroleum hydrocarbons in the environment and discuss their interactions with abiotic and biotic components of the environment under both aerobic and anaerobic conditions. Furthermore, the mechanisms for dealing with petroleum hydrocarbon contamination in the environment will be examined. When petroleum hydrocarbons contaminate land, they start to interact with its surrounding, including physical (dispersion), physiochemical (evaporation, dissolution, sorption), chemical (photo-oxidation, auto-oxidation), and biological (plant and microbial catabolism of hydrocarbons) interactions. As microorganism (including bacteria and fungi) play an important role in the degradation of petroleum hydrocarbons, investigations into the microbial communities within contaminated soils is essential for any bioremediation project. This review highlights the fate of petroleum hydrocarbons in tertial environments, as well as the contributions of different microbial consortia for optimum petroleum hydrocarbon bioremediation potential. The impact of high-throughput metagenomic sequencing in determining the underlying degradation mechanisms is also discussed. This knowledge will aid the development of more efficient, cost-effective commercial bioremediation technologies.
Topics: Biodegradation, Environmental; Ecosystem; Hydrocarbons; Microbiota; Petroleum; Petroleum Pollution
PubMed: 31546774
DOI: 10.3390/molecules24183400 -
Microbiology and Molecular Biology... Dec 2003Recent advances in molecular biology have extended our understanding of the metabolic processes related to microbial transformation of petroleum hydrocarbons. The... (Review)
Review
Recent advances in molecular biology have extended our understanding of the metabolic processes related to microbial transformation of petroleum hydrocarbons. The physiological responses of microorganisms to the presence of hydrocarbons, including cell surface alterations and adaptive mechanisms for uptake and efflux of these substrates, have been characterized. New molecular techniques have enhanced our ability to investigate the dynamics of microbial communities in petroleum-impacted ecosystems. By establishing conditions which maximize rates and extents of microbial growth, hydrocarbon access, and transformation, highly accelerated and bioreactor-based petroleum waste degradation processes have been implemented. Biofilters capable of removing and biodegrading volatile petroleum contaminants in air streams with short substrate-microbe contact times (<60 s) are being used effectively. Microbes are being injected into partially spent petroleum reservoirs to enhance oil recovery. However, these microbial processes have not exhibited consistent and effective performance, primarily because of our inability to control conditions in the subsurface environment. Microbes may be exploited to break stable oilfield emulsions to produce pipeline quality oil. There is interest in replacing physical oil desulfurization processes with biodesulfurization methods through promotion of selective sulfur removal without degradation of associated carbon moieties. However, since microbes require an environment containing some water, a two-phase oil-water system must be established to optimize contact between the microbes and the hydrocarbon, and such an emulsion is not easily created with viscous crude oil. This challenge may be circumvented by application of the technology to more refined gasoline and diesel substrates, where aqueous-hydrocarbon emulsions are more easily generated. Molecular approaches are being used to broaden the substrate specificity and increase the rates and extents of desulfurization. Bacterial processes are being commercialized for removal of H(2)S and sulfoxides from petrochemical waste streams. Microbes also have potential for use in removal of nitrogen from crude oil leading to reduced nitric oxide emissions provided that technical problems similar to those experienced in biodesulfurization can be solved. Enzymes are being exploited to produce added-value products from petroleum substrates, and bacterial biosensors are being used to analyze petroleum-contaminated environments.
Topics: Aerobiosis; Biodegradation, Environmental; Ecosystem; Environmental Pollutants; Hydrocarbons; Petroleum; Soil Microbiology
PubMed: 14665675
DOI: 10.1128/MMBR.67.4.503-549.2003