Woodchip bioreactors for saline leachates denitrification can mitigate agricultural impacts in mediterranean areas: The Campo de Cartagena-Mar Menor environmental issue.

Leachates from intensive agriculture containing high nitrate have been identified as a major cause of the severe eutrophication crisis that impacts Mar Menor (SE Spain), the largest hypersaline coastal lagoon in the Mediterranean basin. A best management practice for removing NO3--N is denitrifying bioreactors. This is the first study to assess the efficiency of citrus woodchips bioreactors in treating agricultural leachates that flow to the Mar Menor via surface discharges. Denitrification capacity, woodchip degradation (by weight loss), formation of potentially harmful compounds, and greenhouse gas (GHG) emissions were assessed. Three bioreactors (6 m × 0.98 m x 1.2 m) filled with citrus woodchips (3 m3 d-1 per bioreactor) through which the untreated ditch water over 1.5 years. Bioreactors were operated at 8 h, 16 h, and 24 h hydraulic residence time respectively, in each bioreactor. The main characteristics of the ditch water were: pH ≈ 7.5-8.0, electrical conductivity ≈ 5-8 dS m-1, dissolved organic carbon ≈6-10 mg L-1, and NO3--N ≈ 22-45 mg L-1. Bioreactors were highly efficient in reducing NO3--N. The average RNO3 in effluents was for the complete experimental period 8 g N m-3 d-1, 10.9 g N m-3 d-1, and 12.6 g N m-3 d-1 for 8, 16 and 24 h residence time, respectively. Nitrate reduction efficiency was modulated by seasonal changes in temperature, with an increasing efficiency in warmer periods (maximum ≈ 85-90% for all hydraulic residence time) and decreasing in colder ones (minimum ≈ 12%, 23% and 41% for hydraulic residence time 8, 16 and 24 h respectively). Woodchips degradation was greatest during the first six months (average ≈ 29% weight loss) in the material above the water level, attributable to aerobic mineralization of the organic carbon, while weight loss was ≈11% in woodchip media continuously below the water level. Dissolved organic carbon, sulfide, ammonium, and soluble phosphorus concentrations in the effluents were mostly low, although some peaks in concentrations occurred. Design consideration must be taken to avoid environmental impacts due to the occasional presence of harmful compounds in the effluents.

Woodchip bioreactors provide sustained denitrification of brine from groundwater desalination plants.

Woodchip bioreactors are widely known as a best management practice to reduce excess nitrate loads that are discharged with agricultural leachates. The aim of this study was to evaluate the performance of citrus woodchip bioreactors for denitrification of brine (electrical conductivity ≈ 17 mS cm-1) from groundwater desalination plants with high nitrate content (NO3--N ≈ 48 mg L-1) in the Campo de Cartagena agricultural watershed, one of the main providers of horticultural products in Europe. The performance was evaluated relative to seasonal changes in temperature, dissolved organic carbon (DOC) provided by woodchips, hydraulic residence time (HRT) and woodchip aging. Bioreactors (capacity 1 m3) operated for 2.5 years (121 weeks) in batch mode (24 h HRT) with three batches per week. Denitrification efficiency was modulated by DOC concentration, temperature, hydraulic residence time and the drying-rewetting cycles. High salinity of brine did not prevent nitrate removal from occurring. The high DOC availability (>25 mg C L-1) during the first ≈48 weeks resulted in high nitrate removal rate (>75%) and nitrate removal efficiency (until ≈ 25 g N m-3 d-1) regardless of temperature. Moreover, the high DOC contents in the effluents during this period may present environmental drawbacks. Denitrification was still high after 2.5 years (reaching ≈9.3 g N m-3 d-1 in week 121), but dependence on warm temperature became more apparent with woodchips aging from week ≈49 onwards. Nitrate removal efficiency was highest on the first weekly batch, immediately after woodchips had been unsaturated for four days. It was attributable to a flush of DOC produced by aerobic microbial metabolism during drying that stimulated denitrification following re-saturation. Hence, alternance of drying-rewetting cycles is an operation practice that increase bioreactors nitrate removal performance.

Bioreactors for brine denitrification produced during polluted groundwater desalination in fertigation areas of SE Spain: batch assays for substrate selection.

Increasing knowledge of nitrate removal using denitrifying bioreactors has illustrated the usefulness of this management practice for treating discharge water from agricultural land uses. The objective of this study was to assess the viability of almond shell, chopped carob, olive bone, and citrus woodchip as carbon media for denitrification of brine with high nitrate load (EC ≈ 20 dS m-1, NO3--N concentration ≈ 65-80 mg NO3--N L-1) in bioreactors. To the authors' knowledge, this is the first test of denitrifying brine using organic wastes as the carbon substrate, and the first use of these carbon media for that purpose. Nitrate removal efficiency and efficiency:cost ratio were considered. The results indicated that the best removal efficiency and cheapest cost were provided by citrus woodchip (3.02 ± 0.15 mg NO3--N m-3 d-1) at a cost of ≈ 6€ m-3, followed by almond shell (1.54 ± 0.20 mg NO3--N m-3 d-1) at a cost of ≈ 19€ m-3. Chopped carob and olive bone showed negligible nitrate removal in the brine; chopped carob generated acidic leachate with extremely high dissolved organic carbon, and olive bone resulted in a highly saline leachate. Of the four media tested, the results of this study indicated that citrus woodchip was the most suitable media for denitrification of the brine.

Darbepoetin inhibits proliferation of hepatic cancer cells in the presence of TGF-ß.

Darbepoetin (DPO), an erythropoietin (EPO) derivative, was licensed in 2002 to treat patients with solid tumors suffering from chemotherapy-dependent anemia, although various tumors express EPO to improve vascularization, thus favoring tumor growth and spreading. Therefore, we wanted to investigate direct effects of DPO on the liver tumor cell lines HepG2, SkHep1, Huh-7, AKN1, HCC-T and HCC-M, as well as on primary human hepatocytes (hHeps). DPO (0-40 ng/ml) did not affect viability of hHeps, HepG2, SkHep1, AKN1, HCC-T and HCC-M cells, as determined by Resazurin conversion. However, Huh-7 cells' viability dose-dependently decreased from 5 ng/ml DPO on. Lack of LDH release into culture medium and negative DNA laddering excluded apoptosis or necrosis as the cause for the reduced Resazurin conversion. In Huh-7 cells, DPO increased the expression of p53. Interestingly, Huh-7 cells showed the highest basal TGF-ß1 expression as compared to the other cell lines. Upon inhibition of TGF-ß1 signaling, DPO no longer reduced viability in Huh-7 cells. On the contrary, co-incubation with TGF-ß1 made the other cell lines responsive to DPO. Summarizing our data, we show that DPO reduces the growth of Huh-7 cells by up-regulation of the tumor-suppressor gene p53. This mechanism seems to be dependent on a strong TGF-ß expression and corresponding signaling in these cells, as other cell lines became responsive to DPO with TGF-ß1 supplementation. The knowledge of this mechanism offers great perspectives for the understanding and treatment of solid liver tumors.

The right choice of antihypertensives protects primary human hepatocytes from ethanol- and recombinant human TGF-ß1-induced cellular damage.

BACKGROUND: Patients with alcoholic liver disease (ALD) often suffer from high blood pressure and rely on antihypertensive treatment. Certain antihypertensives may influence progression of chronic liver disease. Therefore, the aim of this study is to investigate the impact of the commonly used antihypertensives amlodipine, captopril, furosemide, metoprolol, propranolol, and spironolactone on alcohol-induced damage toward human hepatocytes (hHeps). METHODS: hHeps were isolated by collagenase perfusion. Reactive oxygen species (ROS) were measured by fluorescence-based assays. Cellular damage was determined by lactate-dehydrogenase (LDH)-leakage. Expression analysis was performed by reverse-transcription polymerase chain reaction and Western blot. Transforming growth factor (TGF)-ß signaling was investigated by a Smad3/4-responsive luciferase-reporter assay. RESULTS: Ethanol and TGF-ß1 rapidly increased ROS in hHeps, causing a release of 40%-60% of total LDH after 72 hours. All antihypertensives dose dependently reduced ethanol-mediated oxidative stress and cellular damage. Similar results were observed for TGF-ß1-dependent damage, except for furosemide, which had no effect. As a common mechanism, all antihypertensives increased heme-oxygenase-1 (HO-1) expression, and inhibition of HO-1 activity reversed the protective effect of the drugs. Interestingly, Smad3/4 signaling was reduced by all compounds except furosemide, which even enhanced this profibrotic signaling. This effect was mediated by expressional changes of Smad3 and/or Smad4. CONCLUSIONS: Our results suggest that antihypertensives may both positively and negatively influence chronic liver disease progression. Therefore, we propose that in future patients with ALD and high blood pressure, they could benefit from an adjusted antihypertensive therapy with additional antifibrotic effects.