The cell density-dependent gene expression in gram-negative bacteria is through the activity of acyl homoserine lactone signal molecules. The novel strain Pseudomonas putida JMQS1 isolated from detergent-contaminated soil exhibited quorum sensing along with its ability to degrade phenol. The response to Chromobacterium violaceum DSTS-1 mutant biosensor and luxI and luxR gene-specific amplification was used to characterize the quorum sensing property of the isolate. A regulation in the synthesis of various acyl homoserine lactone molecules, viz C₆HSL in the initial stages of phenol stress, C₈HSL during degradation, and 3OC₁₂HSL on completion of degradation could be identified by liquid chromatography-quadrupole time of flight. Thin-layer chromatography, Fourier transform infrared spectroscopy, and gas chromatography mass spectrometry confirmed the complete degradation of phenol in 48–56 h. P. putida JMQS1 exhibited adaptation over phenol stress through the selective activation of the quorum sensing signal molecules depending on the changing physiological conditions. This study proposes an efficient method for enhancing the degradation of toxic organic pollutants by the supplementation of acyl homoserine lactone signal molecules.

Elevated plant-available cadmium (Cd) in soils results in contamination to cacao (Theobroma cacao L) beans. Effectiveness of vermicompost and zeolite in reducing available Cd in three cacao-growing soils was studied under laboratory conditions. Sorption–desorption experiments were conducted in soils and amendments. Cadmium was added at 0 or 5 mg kg⁻¹ (spiked), then, amendments were incorporated at 0, 0.5, or 2 %. Amended soils were incubated at room temperature for 28 days. Plant-available Cd was determined using 0.01 M CaCl₂ (WSE) and Mehlich 3 (M3) extraction procedures in subsamples taken from individual bags at six time intervals. Soils and amendments displayed different sorption characteristics and a better fit was attained with Freundlich model (R ² > 0.82). Amendments were ineffective in reducing extractable Cd in non-spiked soils. In Cd-spiked soils, vermicompost at 2 % significantly reduced WSE-Cd (P < 0.01) from 3.36, 0.54, and 0.38 mg kg⁻¹ to values lower that instrument’s detection in all the three soils and significantly diminished M3-extractable Cd (P < 0.05) from 4.62 to 4.11 mg kg⁻¹ in only one soil. Vermicompost at 0.5 % significantly decreased WSE-Cd (P < 0.01) from 3.04 and 0.31 to 1.69 and 0.20 mg kg⁻¹, respectively, in two soils with low sorption capacity for Cd. In contrast, zeolite failed to reduce WSE- or M3-extractable Cd in all studied soils. A negative correlation occurred between soil pH and WSE-Cd (r > −0.89, P < 0.01). The decrease in WSE-Cd appears to be associated with the increase in pH of the vermicompost-amended soils.

The current experiment was conducted to evaluate the effects of feeding dried sweet orange peel (SOP) and lemon grass leaves (LGL) as feed additives on broiler growth performance, serum metabolites, and antioxidant status. A total of 192-day-old (Ross 308) broiler chickens were distributed randomly into 4 dietary treatments with 4 replicates per each treatment. The dietary treatments included a control diet without any feed additive (T1), a diet containing 0.8 % SOP (T2), a diet containing 0.8 % LGL (T3), and a diet containing combination of 0.4 % SOP + 0.4 % LGL (T4) was fed during the growth period from 22 to 42 days. Feed intake (FI), body weight gain (BWG), feed conversion ratio (FCR), carcass traits, serum components, and antioxidant status were measured. At the end of the experimental period, the results indicated that supplementation of SOP and LGL alone or in combination did not significantly (P > 0.05) affect BWG, FI, FCR, and carcass characteristics in broiler chickens. Serum total protein was increased significantly (P < 0.05) in T3 and T4 compared to the other treatments. Also, serum globulin increased significantly (P < 0.05) in the treated groups. Serum glucose, low density lipoprotein, triglyceride, and very low density lipoprotein decreased significantly (P < 0.05) in the treatment groups, while cholesterol and high-density lipoprotein decreased in T2 compared to the other groups. Significantly (P < 0.05) higher total antioxidant status was observed in T2 compared to the other treatments. In conclusion, these results indicate that SOP, LGL, and their combination may positively modify some serum components and the antioxidant status without any beneficial effect on growth performance and carcass traits in broiler chickens.

A potential source contribution function (PSCF) can indicate the source areas of high air pollutant concentrations using backward trajectories. However, the conventional two-dimensional PSCF (2D-PSCF) cannot consider the emission and transport height of air pollutants. That missing information might be critical because injection height varies depending on the source type, such as with biomass burning. We developed a simple algorithm to account for the height of trajectories with high concentrations and combined it with the conventional PSCF to devise 3D-PSCF. We demonstrate the applicability of the 3D-PSCF by applying it to particulate PAH data collected from September 2006 to August 2007 in Seoul. We found variation in the results from 3D-PSCF with threshold heights from 3,000 to 1,500 m. Applying 2,000 m as the threshold height in the PSCF calculation most clearly determined the possible source areas of air pollutants from biomass fuel burning that were affecting the air quality in Seoul.

The increasing use of herbicides in sugarcane production has increased environmental concern regarding the fate of these compounds, especially when they are used in mixtures. Among the various processes that determine the behavior of molecules in the environment, leaching stands out. In this context, the aim of this study was to evaluate the leaching of a mixture of hexazinone, sulfometuron-methyl, and diuron in soils with contrasting textures. A completely randomized experimental design containing three replications in a 2 × 6 factorial arrangement was used, with two soils (alfisol–Paleudult, sandy clay texture and ultisol–typic Hapludalf, sandy loam texture) and six depths (0–0.05, 0.05–0.10, 0.10–0.15, 0.15–0.20, 0.20–0.25, and 0.25–0.30 m). Three glass columns of 50 cm were used for each soil. The dose used was 391.0 + 33.35 + 1386.9 g a.i. ha⁻¹ of hexazinone, sulfometuron-methyl and diuron, respectively. After applying the mixture to the top of each column, rainfall simulation with 200 mm of 0.01 mol L⁻¹ CaCl₂ solution was applied for 48 h. The leachates were collected at 6, 12, 24, 36, and 48 h. The chromatographic determinations of the herbicides were performed by high-performance liquid chromatography (HPLC) with a UV-Vis detector. For hexazinone, the highest percentage recovery in the soil with a sandy clay texture occurred at a depth of 0.10–0.15 m, with 40 % recovered, while in the soil with a sandy loam texture, the most part was recovered at a depth of 0.25–0.30 m. Diuron demonstrated little mobility in the soil and was detected in most cases only in the surface layer (up to 0.10 m) in both soils. Sulfometuron-methyl, in soil with a sandy clay texture, was detected to a depth of 0.15–0.20 m with the highest concentration found at a depth of 0–0.05 m, while in sandy loam soil, a higher concentration was found at a depth of 0.10–0.15 m; this herbicide was detected down to 0.25–0.30 m. These results show that the soil texture directly influences the leaching of hexazinone, sulfometuron-methyl, and diuron.

In this study, the effects of cypermethrin (CYP), amitraz (AMT) and combined cypermethrin-amitraz (CYP-AMT) on some serum biochemical, oxidative stress and drug-metabolising parameters were investigated in male Wistar albino rats. CYP, AMT and combined CYP-AMT were administered at doses of 80 mg kg⁻¹ bw⁻¹ of CYP and 170 mg kg⁻¹ bw⁻¹ of AMT for 1 day (single dose), and at doses of 12 mg kg⁻¹ bw⁻¹ of CYP and 25 mg kg⁻¹ bw⁻¹ of AMT for 40 days by oral gavage. Oxidative stress (malondialdehyde (MDA), nitric oxide (NO), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and glucose-6-phosphate dehydrogenase (G6PD)), serum biochemical (glucose, triglyceride, cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), blood urea nitrogen (BUN), creatinine, asparatate amino transferase (AST), alanine amino transferase (ALT), alkaline phosphatase (ALP), total protein, albumin) in blood/tissues (liver, kidney, brain, spleen and testis) and hepatic drug-metabolising (cytochrome P450 2E1 (CYP2E1), NADH-cytochrome b₅ reductase (CYPb5), NADPH-cytochrome c reductase/NADPH cytocrome P450 reductase (CYTC), glutathione S-transferase (GST), glutathione (GSH)) parameters were measured in liver samples taken on days 1 and 40. In result, it was determined that CYP, AMT and their combinations led to significant changes in the parameters investigated, and it was ascertained that long-term exposure to insecticides and the administration of insecticide combinations produced greater toxic effects in comparison with the administration of insecticides alone.

In this study, the potential association of (citrate-stabilized) Ag (14.1 ± 1.0 nm) and CeO₂ (6.7 ± 1.2 nm) engineered nanoparticles (ENPs), or their ionic counterparts, with the submerged aquatic plant Elodea canadensis, was examined and, in particular, parameters affecting the distribution of the nanoparticles (or metal ions) between plant biomass and the water phase were assessed using five distinct aqueous matrices (i.e. tap water, 10 % Hoagland’s solution and three natural surface water samples). Individual plants were exposed to varying concentrations of Ag and CeO₂ ENPs or Ag⁺ and Ce³⁺ ions during 72-h-lasting batch experiments. A dose-dependent increase of silver or cerium in plant biomass was observed for both the nanoparticles and the ions, whereby exposure to the latter systematically resulted in significantly higher biomass concentrations. Furthermore, the apparent plant uptake of CeO₂ ENPs appeared to be higher than that for Ag ENPs when comparing similar exposure concentrations. These findings suggest that association with E. canadensis might be affected by particle characteristics such as size, composition, surface charge or surface coating. Moreover, the stability of the ENPs or ions in suspension/solution may be another important aspect affecting plant exposure and uptake. The association of the nanoparticles or ions with E. canadensis was affected by the physicochemical characteristics of the water sample. The silver biomass concentration was found to correlate significantly with the electrical conductivity (EC), dry residue (DR) and Cl⁻, K, Na and Mg content in the case of Ag ENPs or with the EC, inorganic carbon (IC) and Cl⁻, NO₃⁻, Na and Mg content in the case of Ag⁺ ions, whereas significant relationships between the cerium biomass concentration and the EC, DR, IC and Ca content or the pH, EC, DR, IC and Cl⁻, Ca and Mg content were obtained for CeO₂ ENPs or Ce³⁺ ions, respectively. Results also indicated that the Ag ENPs and Ag⁺ ions might potentially be toxic towards E. canadensis whereas no evidence of phytotoxicity was noted in the case of CeO₂ ENPs or Ce³⁺ ions.

Studies on replacement of inorganic fertilizer with organic residues to improve crop productivity and their impact on greenhouse gas emission from agricultural soil merit more attention. Two-year field experiments were conducted to study the impact of different organic residues with varied carbon (C)/nitrogen (N) ratios as substitutes of chemical fertilizer on emission reduction of nitrous oxide (N₂O) and crop yield from a tropical summer rice paddy of India. Five treatments comprising of conventional N fertilizer (NPK), cow manure (CD), rice straw (RS), poultry manure (PM), and sugarcane bagasse (SCB) were applied in a rice field to estimate N₂O emission. Application of CD (at 10 t ha⁻¹) resulted in maximum reduction of seasonal N₂O emissions (15 %) over NPK, RS, PM, and SCB. Application of CD and RS enhanced leaf photosynthetic rate and caused maximum utilization of photosynthates towards developing grains as evident from grain filling ability and higher grain yield. Substitution of NPK with organic residues enhanced soil nutrient availability in terms of C and N resulting in improved soil fertility and to some extent influenced soil nitrogen processes which in turn reduced N₂O emissions. We conclude that suitable management of soil in agricultural ecosystem can reduce the emission of N₂O and protect and preserve the soil health without compromising the agronomic productivity reducing the use of chemical fertilizer and maintaining the sustainability of rice ecosystem as evident from lower carbon equivalent emissions (CEE) and higher carbon efficiency ratio (CER) at CD in rice paddies in the present study.

This paper investigated the influence of various florfenicol concentrations on the treatment effect of greenhouse turtle breeding wastewater by intermittent aeration dynamic membrane bioreactor (IADMBR). The results showed that when the florfenicol concentration reached 80 and 120 ng L⁻¹, the average removal efficiencies of ammonia nitrogen and chemical oxygen demand (COD) decreased by 32 and 48 %, respectively. Thus, the enhanced removal of florfenicol and its maintenance at a low concentration are prerequisites to ensure excellent effluent quality. Orthogonal experiments showed that the optimized IADMBR process parameters were hydraulic retention time (HRT) = 5 h, sludge retention time (SRT) = 30 days, and C/N = 2.5; using this combination, the florfenicol concentration was reduced to 25.8 ng L⁻¹, and the average removal efficiency was as high as 78.5 %. The large-scale field pilot test showed that the optimized IADMBR process not only ensured standardized discharge of greenhouse turtle breeding wastewater but also effectively reduced antibiotic pollution and was thus worthy of use in practical applications.

The concentrations and fractions of cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) in soils collected from Hailuogou Glacier foreland in eastern Tibetan Plateau were analyzed to decipher their mobility, and their eco-risk was assessed combined with multiple environmental indices. The concentrations of Cd were more than ten times higher than its local background in the O horizon and nearly three times higher in the A horizon. The concentrations of Pb and Zn were relatively high in the O horizon, whereas that of Cu increased with soil depth. The main fractions of metals in the surface horizons were reducible and acid-soluble for Cd, oxidizable and residual for Cu, reducible and oxidizable for Pb, and reducible and residual for Zn. The metal mobility generally followed the order of Cd > Pb > Zn > Cu in the O horizon and Cd > Pb > Cu > Zn in the A horizon. Sorption and complexation by soil organic matters imparted an important effect on the mobilization and transformation of Cd, Pb, and Zn in the soils. The oxidizable Cu fraction in the soils showed significant correlation with organic matters, and soil pH mainly modulated the acid-soluble and reducible Cu fractions. The concentrations and other environmental indices including contamination factor, enrichment factor, geoaccumulation index, and risk assessment index revealed that Cd reached high contamination and very high eco-risk, Pb had medium contamination but low eco-risk, Zn showed low contamination and low eco-risk, and Cu was not contaminated in the soils. The data indicated that Cd was the priority to concern in the soils of Hailuogou Glacier catchment.