In situ treatment of Hamilton Harbour sediment

To enhance the biodegradation of organic contaminants, approximately 18.5 tonnes of oxidant (calcium nitrate) and 5 tonnes of nutrients were injected into sediments of the Dofasco Boatslip, Hamilton Harbour. In the laboratory 78% and 68% of the oil (TPHs) and polynuclear aromatic hydrocarbons (PAHs), respectively biodegraded in 197 days. In the 1992 treatment in the Ddofasco Boatslip, biodegradation of organic contaminants varied from 79% for low molecular weight compounds (BTXs), to 25/15 of the 16 priority pollutant PAHs. At first biodegraduation of large molecular weight PAHs resulted in the production of naphthalene (from 280 g/g to 549 g/g). In the 1993 treatments, 94% of the naphthalene, and 57% of the TPHs biodegraded. The in situ biotreatment of organic contamination takes time but for some sites the significantly lower cost relative to dredging and confinement makes in situ treatment a viable alternative.     

Effects of community-accessible biochar and compost on diesel-contaminated soil

Petroleum pollution is a global problem that requires effective and accessible remediation strategies that takes ecosystem functioning into serious consideration. Bioremediation can be an effective tool to address the challenge. In this study, we used a mesocosm experiment to evaluate the effects of locally sourced and community produced biochar and compost amendments on diesel-contaminated soil. At the end of the 90-day experiment, we quantified the effects of the amendments on total petroleum hydrocarbons (C9-C40) (TPH) and soil pH, organic matter, aggregate stability, soil respiration, extractable phosphorus, extractable potassium, and micronutrients (Mg, Fe, Mn, and Zn). We observed significantly higher TPH degradation in compost-amended soils than in controls and soils amended with biochar. We propose that the addition of compost improved TPH biodegradation by augmenting soil nutrient content and microbial activity. Our results suggest that community-accessible compost can improve TPH biodegradation, and that implementation is possible at the community level.     

Comparison of circadian expression of tryptophan hydroxylase isoform mRNAs in the rat pineal gland using real-time PCR

A second gene encoding a functional tryptophan hydroxylase activity has recently been described (TPH2), which is expressed abundantly in brainstem, the primary site of serotonergic neurons in the CNS. As serotonin (5-HT) has an important role as a precursor of the nocturnal synthesis of the pineal gland hormone, melatonin, it was of interest to determine the relative expression of TPH1 and 2 mRNA in the rat pineal during the light:dark (L:D) cycle using sensitive real-time RT-PCR assays which were developed for each TPH isoform. TPH1 mRNA expression was 105-fold more abundant in rat pineal than TPH2, and showed a significant approximately 4-fold nocturnal increase in expression which may contribute to the previously described nocturnal increase in pineal tryptophan hydroxylase activity. TPH2 expression within the gland showed no significant variation with time of day and was very low (approximately 300 copies/gland) indicating expression in the small proportion of "non-pinealocyte" cells in the gland.     

Nitrogen Cycling and Nitric Oxide Emissions in Oil-Impacted Prairie Soils

A remote site in the Tallgrass Prairie Preserve of Oklahoma (The Nature Conservancy) was contaminated with crude oil from a pipeline break and is being bioremediated using landfarming techniques. Landfarming is designed to stimulate microbial-based catabolism of petroleum through combined dilution/mixing and fertilization-based effects. To evaluate nitrogen-based effects during remediation, the site was sectioned and treated with urea, ammonium sulfate, or ammonium nitrate. Samples were obtained from prairie soil without chemical nitrogen addition and with or without hydrocarbon contamination. Nitrogen cycling dynamics were followed by measuring ammonium, nitrite, nitrate, and volatile nitric oxide (NO_x) levels. Nitrifying and denitrifying bacterial numbers were estimated and compared to soil oxygen, carbon dioxide, and methane levels as well as to overall total petroleum hydrocarbon (TPH) reduction. For a prairie ecosystem of this type, a high level of fertilization, particularly with nitrogen, can have ecological effects almost as profound as the petroleum contamination itself. Fertilization of the oil-contaminated soil with the reduced and/or oxidized forms of nitrogen quickly resulted in elevated steady-state levels of both ammonium and nitrate, and exceptionally high levels of NO_x released from soil. Although nitrogen fertilization increased microbial nitrogen metabolism and nitrogen cycling, it had minimal effects on the overall remediation efficiency.     

Brain serotonin deficiency leads to social communication deficits in mice

A deficit in brain serotonin is thought to be associated with deteriorated stress coping behaviour, affective disorders and exaggerated violence. We challenged this hypothesis in mice with a brain-specific serotonin depletion caused by a tryptophan hydroxylase 2 (TPH2) deficiency. We tested TPH2-deficient (Tph2^−/–) animals in two social situations. As juveniles, Tph2^−/− mice displayed reduced social contacts, whereas ultrasonic vocalizations (USVs) were unchanged within same-sex same-genotype pairings. Interestingly, juvenile females vocalized more than males across genotypes. Sexually naive adult males were exposed to fresh male or female urine, followed by an interaction with a conspecific, and re-exposed to urine. Although Tph2^−/− mice showed normal sexual preference, they were hyper-aggressive towards their interaction partners and did not vocalize in response to sexual cues. These results highlight that central serotonin is essential for prosocial behaviour, especially USV production in adulthood, but not for sexual preference.     

Enhancement of Hydrocarbon Removal in a Clay and Drilling-Waste Polluted Soil

The application of biological processes in restoring oil polluted sites is growing due to their efficiency in removing different classes of pollutants. The aim of this study was to determine the ability of microorganisms present in a drilling-waste polluted soil (36,200 mg TPH kg^?1 soil) to remove weathered hydrocarbons under stimulated and non-stimulated soil conditions. The hypothesis under study was whether petroleum hydrocarbons removal could be enhanced by manipulating C/N ratio, water content and addition of three agroindustrial wastes. A Box-Behnken design was employed to evaluate the effect of each variable. Results demonstrated that, for orange peels and banana trunk treatments, the variable with the largest effect (p < 0.01) on hydrocarbon removal was the C/N ratio, indicating that higher ratio (100/3) improved removal (79.5–82%). The largest effect (p < 0.001) on hydrocarbon removal for pineapple wastes was observed with higher water content (60%) achieving the highest removal (89%). After 90 days of experimentation, the type of agricultural waste and the agricultural waste/soil ratio were not statistically significant in any treatment. However, their addition was important relative to non-stimulated soil, which showed a hydrocarbon removal of 17%. Data reported in this study showed the application of bioremediation in clay and drilling waste-polluted soils.     

Bioremediation of Soil Contaminated with Diesel Using Inorganic Nitrogen Sources: Incorporating nth-Order Algorithm in the Evaluation of Process Kinetics

In the present study, we investigated the effects of inorganic nitrogen sources—(NPK fertilizer, 15:15:15), (urea fertilizer, 46:0:0), (NH₄)₂SO₄ as well as monitored natural attenuation on the bioremediation of diesel-polluted soil. At the end of the 6-week study, the highest degradation was recorded in soil amended with NPK fertilizer (95 ± 2.77%) while the least total petroleum hydrocarbon removal was observed in monitored natural attenuation (89 ± 2.91%). Nth-order kinetics effectively described three of the treatments out of the four treatment plans. These include urea amendment (r² = 0.9925, average relative error (ARE) = 1.45%, root mean square error (RMSE) = 0.038, k_n = (3.57 ± 0.61) × 10^?2, n = 1.33), NPK fertilizer amendment (r² = 0.9751, ARE = 3.241%, RMSE = 0.086, k_n = (8.04 ± 0.23) × 10^?1, n = 0.74), and monitored natural attenuation (r² = 0.9697, ARE = 2.77%, RMSE = 0.073, k_n = (1.57 ± 0.50) × 10^?2, n = 1.16). The values of n from the nth-order kinetics parameter estimation indicated that all the treatments resulted in diesel degradation that followed a first-order kinetics path. Thus, the outcome of kinetic modeling showed that nth-order can be used as validating tool when many kinetic orders are under consideration. The phytotoxicity assay with Zea mays showed that the treatments plans resulted in germination indices of 17–55%.     

Phytoremediation Effect and Growth Responses of Cynodon spp. and Agropyron desertorum in a Petroleum-Contaminated Soil

In order to compare the petroleum tolerance and phytoremediation ability of a native grass, Agropyron desertorum (desert Wheatgrass) with Cynodon spp. (Bermuda grass) in a petroleum hydrocarbon-contaminated soil, a 7-month greenhouse experiment was performed. There were 4 soil treatments with 0% (uncontaminated soil), 2%, 4%, and 12% (w_oil/w_soil) petroleum concentration. Parameters including shoot and root fresh weight and dry weight, root penetration depth and root density depth, soil respiration, and total petroleum hydrocarbons (TPH) degradation were measured during and after experiments. The results showed an increase in shoot fresh weight of A. desertorum in soil polluted with 2% petroleum sludge compared to the uncontaminated soil, whereas the growth of Bermuda grass significantly decreased in corresponding treatment. Root growth of A. desertorum was decreased in 2% and 4% petroleum sludge, whereas it was increased in Bermuda grass species. Overall, root fresh weight of Bermuda grass was higher than that of A. desertorum in all treatments. Significant increase in microorganisms' activity was observed in the presence of petroleum sludge and plants in soil compared with uncontaminated soil without plants, and the highest soil respiration (37.6 mg C-CO₂/kg soil day) has been observed in the rhizosphere of Bermuda grass in treatment with 12% petroleum sludge. Plants had a significant role in the degradation of soil contaminants as TPH degradation in planted soils was significantly higher than that in unplanted soil (TPH degradation (%) was 30.4 and 38.9 in A. desertorum and Bermuda grass, respectively, whereas it was just 13.3 in unplanted soil). The rhizosphere of Bermuda grass had significantly less residual TPHs compared to A. desertorum. The results indicated that both Cynodon spp. and A. desertorum had a peculiar tolerance to petroleum pollution. Therefore, as Bermuda grass has already been suggested to be a typical and efficient species for phytoremediating petroleum-contaminated sites, A. desertorum may also prove to be a suitable native alternative.     

Requirement of tryptophan hydroxylase during development for maturation of sensorimotor gating

Deficits in sensorimotor gating, a function to focus on the most salient stimulus, could lead to a breakdown of cognitive integrity, and could reflect the "flooding" by sensory overload and cognitive fragmentation seen in schizophrenia. Sensorimotor gating emerges at infancy, and matures during childhood. The mechanisms that underlie its development are largely unclear. Here, we screened the mouse genome, and found that tryptophan hydroxylase (TPH) is implicated in the maturation of sensorimotor gating. TPH, an enzyme involved in the biosynthesis of serotonin, proved to be required only during the weaning period for maturation of sensorimotor gating, but was dispensable for its emergence. Proper serotonin levels during development underlie the mature functional architecture for sensorimotor gating via appropriate actin polymerization. Thus, maintaining proper serotonin levels during childhood may be important for mature sensorimotor gating in adulthood.