Pseudomonas, the dominant polycyclic aromatic hydrocarbon-degrading bacteria isolated from Antarctic soils and the role of large plasmids in horizontal gene transfer

A most-probable-number (MPN) procedure was developed to separately enumerate aliphatic and aromatic hydrocarbon degrading bacteria, because most of the currently available methods are unable to distinguish between these two groups. Separate 96-well microtiter plates are used to estimate the sizes of these two populations. The alkane-degrader MPN method uses hexadecane as the selective growth substrate and positive wells are detected by reduction of iodonitrotetrazolium violet, which is added after incubation for 2 weeks at 20 °C. Polycyclic aromatic hydrocarbon degraders are grown on a mixture of phenanthrene, anthracene, fluorene, and dibenzothiophene in a second plate. Positive wells turn yellow to greenish-brown from accumulation of the partial oxidation products of the aromatic substrates and they can be scored after a 3-week incubation period. These MPN procedures are accurate and selective. For pure cultures, heterotrophic plate counts on a nonselective medium and the appropriate MPN procedure provide similar estimates of the population density. Bacteria that cannot grow on the selective substrates do not produce false positive responses even when the inoculum density is very high. Thus, this method, which is simple enough for use in the field, provides reliable estimates for the density and composition of hydrocarbon-degrading microbial populations.Key words: most probable number, polycyclic aromatic hydrocarbon, alkane, hydrocarbon, bacteria.

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Gas-phase route to polycyclic aromatic hydrocarbon formation in protoplanetary atmospheres: role of stabilized benzyne anions

Monthly Notices of the Royal Astronomical Society ◽

10.1111/j.1365-2966.2011.18711.x ◽

2011 ◽

Vol 415 (1) ◽

pp. 425-430 ◽

Cited By ~ 15

Author(s):

F. Carelli ◽

F. Sebastianelli ◽

M. Satta ◽

F. A. Gianturco

Keyword(s):

Polycyclic Aromatic Hydrocarbon ◽

Aromatic Hydrocarbon ◽

Gas Phase ◽

Polycyclic Aromatic ◽

Hydrocarbon Formation

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A polycyclic aromatic hydrocarbon-enriched environmental chemical mixture enhances AhR, antiapoptotic signaling and a proliferative phenotype in breast cancer cells

Carcinogenesis ◽

10.1093/carcin/bgaa047 ◽

2020 ◽

Author(s):

Larisa M Gearhart-Serna ◽

John B Davis ◽

Mohit Kumar Jolly ◽

Nishad Jayasundara ◽

Scott J Sauer ◽

...

Keyword(s):

Breast Cancer ◽

Polycyclic Aromatic Hydrocarbon ◽

Aromatic Hydrocarbon ◽

Cancer Cells ◽

Breast Cancer Cells ◽

Complex Mixture ◽

Environmental Chemicals ◽

Er Positive ◽

Polycyclic Aromatic

Abstract Emerging evidence suggests the role of environmental chemicals, in particular endocrine-disrupting chemicals (EDCs), in progression of breast cancer and treatment resistance, which can impact survival outcomes. However, most research tends to focus on tumor etiology and the effect of single chemicals, offering little insight into the effects of realistic complex mixture exposures on tumor progression. Herein, we investigated the effect of a polycyclic aromatic hydrocarbon (PAH)-enriched EDC mixture in a panel of normal and breast cancer cells and in a tumor organoid model. Cells or organoids in culture were treated with EDC mixture at doses estimated from US adult intake of the top four PAH compounds within the mixture from the National Health and Nutrition Examination Survey database. We demonstrate that low-dose PAH mixture (6, 30 and 300 nM) increased aryl hydrocarbon receptor (AhR) expression and CYP activity in estrogen receptor (ER) positive but not normal mammary or ER-negative breast cancer cells, and that upregulated AhR signaling corresponded with increased cell proliferation and expression of antiapoptotic and antioxidant proteins XIAP and SOD1. We employed a mathematical model to validate PAH-mediated increases in AhR and XIAP expression in the MCF-7 ER-positive cell line. Furthermore, the PAH mixture caused significant growth increases in ER-negative breast cancer cell derived 3D tumor organoids, providing further evidence for the role of a natural-derived PAH mixture in enhancing a tumor proliferative phenotype. Together, our integrated cell signaling, computational and phenotype analysis reveals the underlying mechanisms of EDC mixtures in breast cancer progression and survival.

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