We studied the mineralization of pyrene, carbazole, and benzoapyrene in soils obtained from three abandoned coal gasification plants in southern Illinois. The soils had different histories of past ...exposure to hydrocarbon contamination and different amounts of total organic carbon, microbial biomass, and microbial activity. Mineralization was measured by using serum bottle radiorespirometry. The levels of indigenous mineralization of 14C-labeled compounds ranged from 10 to 48% for pyrene, from undetectable to 46% for carbazole, and from undetectable to 25% for benzoapyrene following long-term ( 180-day) incubations. Pyrene and carbazole were degraded with short or no lag periods in all soils, but benzoapyrene mineralization occurred after a 28-day lag period. Mineralization was not dependent on high levels of microbial biomass and activity in the soils. Bacterial cultures that were capable of degrading pyrene and carbazole were isolated by enrichment, grown in pure culture, and reintroduced into soils. Reintroduction of a pyrene-degrading bacterium enhanced mineralization to a level of 55% within 2 days, compared with a level of 1% for the indigenous population. The carbazole degrader enhanced mineralization to a level of 45% after 7 days in a soil that showed little indigenous carbazole mineralization. The pyrene and carbazole degraders which we isolated were identified as a Mycobacterium sp. and a Xanthamonas sp., respectively. Our results indicated that mineralization of aromatic hydrocarbons can be significantly enhanced by reintroducing isolated polycyclic aromatic hydrocarbon-degrading bacteria
An appreciation for the importance of structural complexity, combined with the acknowledgment that stands with complex structures are uncommon compared to pre-European settlement estimates, has led ...to a growing interest in restoring late-successional forests. The success of these projects is dependent upon our understanding of the variability of late-successional structure and the disturbance events that produced this structure. We quantified woody species composition, stand structure, canopy disturbance history, and Quercus establishment and canopy accession patterns to document processes that resulted in the structural conditions of an upland hardwood forest in Tennessee. The forest established in the mid-1800s and exhibited structural characteristics that were within the range of what has been reported from other late-successional forests in the region. The forest overstory was dominated by Quercus prinus, but Acer saccharum was the most abundant species. Quercus recruitment was continuous from stand initiation through the 1950s. The vast majority of Quercus trees that established prior to 1880 established in closed canopy conditions, whereas most Quercus trees that established after 1880 established in high light environments. Quercus establishment in canopy gaps resulted in multi-aged Quercus populations in the forest. We documented three forest-wide disturbances during development (1922, 1945, and 1973). The 1922 forest-wide disturbance coincided with an establishment pulse of largely understory taxa, and the broad-scale event of 1945 corresponded with an establishment pulse of A. saccharum. Our results provide benchmarks for a region that lacks other reference conditions and can be used to inform structure and process based restoration approaches.
This research addressed the effect of mineral and organic soil constituents on the fate of organic compounds in soils. Specifically, it sought to determine how the associations between organic ...chemicals and different soil constituents affect their subsequent biodegradation in soil. Four 14C-labeled surfactants were aseptically adsorbed to montmorillonite, kaolinite, illite, sand, and humic acids. These complexes were mixed with a woodlot soil, and 14CO2 production was measured over time. The mineralization data were fitted to various production models by nonlinear regression, and a mixed (3/2)-order model was found to most accurately describe the mineralization patterns. Different mineralization patterns were observed as a function of the chemical and soil constituents. Surfactants that had been preadsorbed to sand or kaolinite usually showed similar mineralization kinetics to the control treatments, in which the surfactants were added to the soil as an aqueous solution. Surfactants that had been bound to illite or montmorillonite were typically degraded to lesser extents than the other forms, while surfactant humic acid complexes were degraded more slowly than the other forms. The desorption coefficients (Kd) of the soil constituent-bound surfactants were negatively correlated with the initial rates of degradation (k1) and estimates of 14CO2 yield (P0) as well as actual total yields of 14CO2. However, there was no relationship between Kd and second-stage zero-order rates of mineralization (k0). Microbial community characteristics (biomass and activity) were not correlated with any of the mineralization kinetic parameters. Overall, this study showed that environmental form had a profound effect on the ultimate fate of biodegradable chemicals in soil. This form is defined by the physicochemical characteristics of the chemical, the composition and mineralogy of the soil, and the mode of entry of the chemical into the soil environment
Methylquinolines and related N-heterocyclic aromatic compounds are common contaminants associated with the use of hydrocarbons in both coal gasification and wood treatment processes. These compounds ...have been found in groundwater, and many are known mutagens. A stable, five-member bacterial consortium able to degrade 4-methylquinoline was established by selective enrichment using soil collected from an abandoned coal gasification site. The consortium was maintained for 5 years by serial transfer in a medium containing 4-methylquinoline. A gram-negative soil bacterium, strain Lep1, was isolated from the consortium and shown to utilize 4-methylquinoline as a source of carbon and energy during growth in liquid medium. A time course experiment demonstrated that both the isolate Lep1 and the consortium containing Lep1 were able to degrade 4-methylquinoline under aerobic conditions. Complete degradation of 4-methylquinoline by either strain Lep1 alone or the consortium was characterized by the production and eventual disappearance of 2-hydroxy-4-methylquinoline, followed by the appearance and persistence of a second metabolite tentatively identified as a hydroxy-4-methylcoumarin. Currently, there is no indication that 4-methylquinoline degradation proceeds differently in the consortium culture compared with Lep1 alone. This is the first report of 4-methylquinoline biodegradation under aerobic conditions
An appreciation for the importance of structural complexity, combined with the acknowledgment that stands with complex structures are uncommon compared to pre-European settlement estimates, has led ...to a growing interest in restoring late-successional forests. The success of these projects is dependent upon our understanding of the variability of late-successional structure and the disturbance events that produced this structure. We quantified woody species composition, stand structure, canopy disturbance history, and Quercus establishment and canopy accession patterns to document processes that resulted in the structural conditions of an upland hardwood forest in Tennessee. The forest established in the mid-1800s and exhibited structural characteristics that were within the range of what has been reported from other late-successional forests in the region. The forest overstory was dominated by Quercus prinus, but Acer saccharum was the most abundant species. Quercus recruitment was continuous from stand initiation through the 1950s. The vast majority of Quercus trees that established prior to 1880 established in closed canopy conditions, whereas most Quercus trees that established after 1880 established in high light environments. Quercus establishment in canopy gaps resulted in multi-aged Quercus populations in the forest. We documented three forest-wide disturbances during development (1922, 1945, and 1973). The 1922 forest-wide disturbance coincided with an establishment pulse of largely understory taxa, and the broad-scale event of 1945 corresponded with an establishment pulse of A. saccharum. Our results provide benchmarks for a region that lacks other reference conditions and can be used to inform structure and process based restoration approaches.
The structure named Rebel’s Rest was a two-story, Reconstruction-era house located on the campus of the University of the South in Sewanee, Tennessee, before being severely damaged by fire in July ...2014. The house was constructed of squared timbers and round logs, with later additions built using sawn lumber. Dendrochronological analyses of timbers and logs salvaged from the house reveals wood from four genera: oak (Quercus spp.), tulip poplar (Liriodendron tulipifera L.), American chestnut (Castanea dentata Marshall Borkh.), and pine (Pinus spp.). We statistically and graphically crossdated a total of 251 samples (24,410 rings) with regional chronologies from the ITRDB, resulting in three dated chronologies comprised of oak (1645–1874), tulip poplar (1725–1865), and American chestnut (1710–1864). The majority of samples with cutting dates (95.6%) ended in years 1865–1866, confirming the historically reported construction date of 1866 for the initial structure. The cutting date analysis also confirms two rooms as later additions, Room M (1867) and Room B (1875). Based on ring count and the number of chronologies produced, this research represents the largest known dataset from a single historic structure in the Southeastern US.
For many intraoperative decisions surgeons depend on frozen section pathology, a technique developed over 150 y ago. Technical innovations that permit rapid molecular characterization of tissue ...samples at the time of surgery are needed. Here, using desorption electrospray ionization (DESI) MS, we rapidly detect the tumor metabolite 2-hydroxyglutarate (2-HG) from tissue sections of surgically resected gliomas, under ambient conditions and without complex or time-consuming preparation. With DESI MS, we identify isocitrate dehydrogenase 1-mutant tumors with both high sensitivity and specificity within minutes, immediately providing critical diagnostic, prognostic, and predictive information. Imaging tissue sections with DESI MS shows that the 2-HG signal overlaps with areas of tumor and that 2-HG levels correlate with tumor content, thereby indicating tumor margins. Mapping the 2-HG signal onto 3D MRI reconstructions of tumors allows the integration of molecular and radiologic information for enhanced clinical decision making. We also validate the methodology and its deployment in the operating room: We have installed a mass spectrometer in our Advanced Multimodality Image Guided Operating (AMIGO) suite and demonstrate the molecular analysis of surgical tissue during brain surgery. This work indicates that metabolite-imaging MS could transform many aspects of surgical care.
Modulation of the human polymorphonuclear leukocyte (PMN) respiratory burst by selective cyclic 3',5' adenosine monophosphate (cAMP) phosphodiesterase (PDE) inhibitors was studied with respect to PDE ...isozyme characteristics. Zaprinast, an inhibitor of a cyclic guanosine monophosphate (cGMP)-specific PDE (PDE I), at concentrations up to 100 mumol/L, had no significant effect on the respiratory burst. Milrinone and imazodan, inhibitors of cAMP-metabolizing, cGMP-sensitive PDE (PDE III), reduced the respiratory burst to 60% of control magnitude but only had significant effects when they were introduced at high (100 mumol/L) concentrations. In contrast, rolipram and RO 20-1724, inhibitors of a cAMP-metabolizing, cGMP-insensitive PDE (PDE IV), had significant effects at low concentrations (0.1 mumol/L) and caused marked reduction of the respiratory burst at higher concentrations (25% of control at 10 mumol/L). The selective PDE IV inhibitors significantly potentiated PMN inhibition by isoproterenol. Diethylaminoethyl (DEAE)-Sepharose chromatography demonstrated a predominant PDE isozyme with high affinity and selectivity for cAMP that was insensitive to cGMP and was completely inhibited by rolipram, a PDE IV inhibitor. These results are consistent with the conclusion that the PMN respiratory burst is inhibited by an elevation of cAMP induced by PDE IV inhibition.
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