Laboratory test of suspended sediment effects on short‐term survival and swimming performance of juvenile Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus,Mitchill, 1815)

Tested was the hypothesis that juvenile Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) would exhibit no response in short‐term survival or swimming performance when exposed to varying concentrations of suspended sediment simulating dredge plumes in waterways where this species may be impacted by dredging operations. Sediment collected from Savannah Harbor, South Carolina, USA was used to simulate a worst‐case scenario. Juvenile sturgeon were contained for a 3‐day period in flow‐through aquaria, with limited opportunity for movement, in sediment of varying concentrations (100, 250 and 500 mg L^?1 total suspended solids [TSS]) mimicking prolonged exposure to suspended sediment plumes near an operating dredge. Of the 90 fish exposed, 86 (96%) survived the test. Of the four fish that died, one was exposed to 250 TSS and three to 500 TSS. Swimming performance results indicated that nearly all fish were positively rheotactic. Critical swim speeds (U_crits) were moderate, whether measured as absolute values (21–31 cm s^?1) or as relative values (1.4–2.1 body lengths s^?1), with no significant differences among treatments (F < 0.83, P ≥ 0.4874). Behavior was dominated by contact‐based locomotion and station‐holding. Absence of substantial or significant immediate effects on survival and swimming performance suggest that impacts of sediment plumes in nature, where fish have freedom of movement and the power to escape rapidly, are minimal.     

Acute Toxicity,Respiratory Reaction,and Sensitivity of Three Cyprinid Fish Species Caused by Exposure to Four Heavy Metals

Using 3 cyprinid fish species zebra fish, rare minnow, and juvenile grass carp, we conducted assays of lethal reaction and ventilatory response to analyze sensitivity of the fish to 4 heavy metals. Our results showed that the 96 h LC₅₀ of Hg²⁺ to zebra fish, juvenile grass carp, and rare minnow were 0.14 mg L⁻¹, 0.23 mg L⁻¹, and 0.10 mg L⁻¹, respectively; of Cu²⁺0.17 mg L⁻¹, 0.09 mg L⁻¹, and 0.12 mg L⁻¹ respectively; of Cd²⁺6.5 mg L⁻¹, 18.47 mg L⁻¹, 5.36 mg L⁻¹, respectively; and of Zn²⁺44.48 mg L⁻¹, 31.37 mg L⁻¹, and 12.74 mg L⁻¹, respectively. Under a 1-h exposure, the ventilatory response to the different heavy metals varied. Ventilatory frequency (Vf) and amplitude (Va) increased in zebra fish, juvenile grass carp, and rare minnows exposed to Hg²⁺ and Cu²⁺ (P<0.05), and the Vf and Va of the 3 species rose initially and then declined when exposed to Cd²⁺. Zn²⁺ had markedly different toxic effects than the other heavy metals, whose Vf and Va gradually decreased with increasing exposure concentration (P<0.05). The rare minnow was the most highly susceptible of the 3 fish species to the heavy metals, with threshold effect concentrations (TEC) of 0.019 mg L⁻¹, 0.046 mg L⁻¹, 2.142 mg L⁻¹, and 0.633 mg L⁻¹ for Hg²⁺, Cu²⁺, Cd²⁺, and Zn²⁺, respectively. Therefore, it is feasible to use ventilatory parameters as a biomarker for evaluating the pollution toxicity of metals and to recognize early warning signs by using rare minnows as a sensor.     

Anilofos Tolerance and Its Mineralization by the Cyanobacterium Synechocystis sp. Strain PUPCCC 64

This study deals with anilofos tolerance and its mineralization by the common rice field cyanobacterium Synechocystis sp. strain PUPCCC 64. The organism tolerated anilofos up to 25 mg L⁻¹. The herbicide caused inhibitory effects on photosynthetic pigments of the test organism in a dose-dependent manner. The organism exhibited 60, 89, 96, 85 and 79% decrease in chlorophyll a, carotenoids, phycocyanin, allophycocyanin and phycoerythrin, respectively, in 20 mg L⁻¹ anilofos on day six. Activities of superoxide dismutase, catalase and peroxidase increased by 1.04 to 1.80 times over control cultures in presence of 20 mg L⁻¹ anilofos. Glutathione content decreased by 26% while proline content was unaffected by 20 mg L⁻¹ anilofos. The test organism showed intracellular uptake and metabolized the herbicide. Uptake of herbicide by test organism was fast during initial six hours followed by slow uptake until 120 hours. The organism exhibited maximum anilofos removal at 100 mg protein L⁻¹, pH 8.0 and 30°C. Its growth in phosphate deficient basal medium in the presence of anilofos (2.5 mg L⁻¹) indicated that herbicide was used by the strain PUPCCC 64 as a source of phosphate.     

Sedimentation and overfishing drive changes in early succession and coral recruitment

Sedimentation and overfishing are important local stressors on coral reefs that can independently result in declines in coral recruitment and shifts to algal-dominated states. However, the role of herbivory in driving recovery across environmental gradients is often unclear. Here we investigate early successional benthic communities and coral recruitment across a sediment gradient in Palau, Micronesia over a 12-month period. Total sedimentation rates measured by ‘TurfPods’ varied from 0.03 ± 0.1 SE mg cm⁻² d⁻¹ at offshore sites to 1.32 ± 0.2 mg cm⁻² d⁻¹ at inshore sites. To assess benthic succession, three-dimensional settlement tiles were deployed at sites with experimental cages used to exclude tile access to larger herbivorous fish. Benthic assemblages exhibited rapid transitions across the sediment gradient within three months of deployment. At low levels of sedimentation (less than 0.6 mg cm⁻² d⁻¹), herbivory resulted in communities dominated by coral recruitment inducers (short turf algae and crustose coralline algae), whereas exclusion of herbivores resulted in the overgrowth of coral inhibitors (encrusting and upright foliose macroalgae). An ‘inducer threshold’ was found under increasing levels of sedimentation (greater than 0.6 mg cm⁻² d⁻¹), with coral inducers having limited to no presence in communities, and herbivore access to tiles resulted in sediment-laden turf algal assemblages, while exclusion of herbivores resulted in invertebrates (sponges, ascidians) and terrestrial sediment accumulation. A ‘coral recruitment threshold’ was found at 0.8 mg cm⁻² d⁻¹, below which net coral recruitment was reduced by 50% in the absence of herbivores, while recruitment was minimal above the threshold. Our results highlight nonlinear trajectories of benthic succession across sediment gradients and identify strong interactions between sediment and herbivory that have cascading effects on coral recruitment. Local management strategies that aim to reduce sedimentation and turbidity and manage herbivore fisheries can have measurable effects on benthic community succession and coral recruitment, enhancing reef resilience and driving coral recovery.     

Soil TPH Concentration Estimation Using Vegetation Indices in an Oil Polluted Area of Eastern China

Assessing oil pollution using traditional field-based methods over large areas is difficult and expensive. Remote sensing technologies with good spatial and temporal coverage might provide an alternative for monitoring oil pollution by recording the spectral signals of plants growing in polluted soils. Total petroleum hydrocarbon concentrations of soils and the hyperspectral canopy reflectance were measured in wetlands dominated by reeds (Phragmites australis) around oil wells that have been producing oil for approximately 10 years in the Yellow River Delta, eastern China to evaluate the potential of vegetation indices and red edge parameters to estimate soil oil pollution. The detrimental effect of oil pollution on reed communities was confirmed by the evidence that the aboveground biomass decreased from 1076.5 g m⁻² to 5.3 g m⁻² with increasing total petroleum hydrocarbon concentrations ranging from 9.45 mg kg⁻¹ to 652 mg kg⁻¹. The modified chlorophyll absorption ratio index (MCARI) best estimated soil TPH concentration among 20 vegetation indices. The linear model involving MCARI had the highest coefficient of determination (R ² = 0.73) and accuracy of prediction (RMSE = 104.2 mg kg⁻¹). For other vegetation indices and red edge parameters, the R² and RMSE values ranged from 0.64 to 0.71 and from 120.2 mg kg⁻¹ to 106.8 mg kg⁻¹ respectively. The traditional broadband normalized difference vegetation index (NDVI), one of the broadband multispectral vegetation indices (BMVIs), produced a prediction (R ² = 0.70 and RMSE = 110.1 mg kg⁻¹) similar to that of MCARI. These results corroborated the potential of remote sensing for assessing soil oil pollution in large areas. Traditional BMVIs are still of great value in monitoring soil oil pollution when hyperspectral data are unavailable.     

Biosorption of Methylene Blue by De-Oiled Algal Biomass: Equilibrium,Kinetics and Artificial Neural Network Modelling

The main objective of the present study is to effectively utilize the de-oiled algal biomass (DAB) to minimize the waste streams from algal biofuel by using it as an adsorbent. Methylene blue (MB) was used as a sorbate for evaluating the potential of DAB as a biosorbent. The DAB was characterized by SEM, FTIR, pH_PZC, particle size, pore volume and pore diameter to understand the biosorption mechanism. The equilibrium studies were carried out by variation in different parameters, i.e., pH (2–9), temperature (293.16–323.16 K), biosorbent dosage (1–10 g L⁻¹), contact time (0–1,440 min), agitation speed (0–150 rpm) and dye concentration (25–2,500 mg L⁻¹). MB removal was greater than 90% in both acidic and basic pH. The optimum result of MB removal was found at 5–7 g L⁻¹ DAB concentration. DAB removes 86% dye in 5 minutes under static conditions and nearly 100% in 24 hours when agitated at 150 rpm. The highest adsorption capacity was found 139.11 mg g⁻¹ at 2,000 mg L⁻¹ initial MB concentration. The process attained equilibrium in 24 hours. It is an endothermic process whose spontaneity increases with temperature. MB biosorption by DAB follows pseudo-second order kinetics. Artificial neural network (ANN) model also validates the experimental dye removal efficiency (R² = 0.97) corresponding with theoretically predicted values. Sensitivity analysis suggests that temperature and agitation speed affect the process most with 23.62% and 21.08% influence on MB biosorption, respectively. Dye adsorption capacity of DAB in fixed bed column was 107.57 mg g⁻¹ in preliminary study while it went up to 139.11 mg g⁻¹ in batch studies. The probable mechanism for biosorption in this study is chemisorptions via surface active charges in the initial phase followed by physical sorption by occupying pores of DAB.     

The Influence of Sulphate Deposition on the Seasonal Variation of Peat Pore Water Methyl Hg in a Boreal Mire

In this paper we investigate the hypothesis that long-term sulphate (SO₄ ²⁻) deposition has made peatlands a larger source of methyl mercury (MeHg) to remote boreal lakes. This was done on experimental plots at a boreal, low sedge mire where the effect of long-term addition of SO₄ ²⁻ on peat pore water MeHg concentrations was observed weekly throughout the snow-free portion of 1999. The additions of SO₄ ²⁻ started in 1995. The seasonal mean of the pore water MeHg concentrations on the plots with 17 kg ha⁻¹ yr⁻¹ of sulphur (S) addition (1.3±0.08 ng L⁻¹, SE; n = 44) was significantly (p<0.0001) higher than the mean MeHg concentration on the plots with 3 kg ha⁻¹ yr⁻¹ of ambient S deposition (0.6±0.02 ng L⁻¹, SE; n = 44). The temporal variation in pore water MeHg concentrations during the snow free season was larger in the S-addition plots, with an amplitude of >2 ng L⁻¹ compared to +/−0.5 ng L⁻¹ in the ambient S deposition plots. The concentrations of pore water MeHg in the S-addition plots were positively correlated (r² = 0.21; p = 0.001) to the groundwater level, with the lowest concentrations of MeHg during the period with the lowest groundwater levels. The pore water MeHg concentrations were not correlated to total Hg, DOC concentration or pH. The results from this study indicate that the persistently higher pore water concentrations of MeHg in the S-addition plots are caused by the long-term additions of SO₄ ²⁻ to the mire surface. Since these waters are an important source of runoff, the results support the hypothesis that SO₄ ²⁻ deposition has increased the contribution of peatlands to MeHg in downstream aquatic systems. This would mean that the increased deposition of SO₄ ²⁻ in acid rain has contributed to the modern increase in the MeHg burdens of remote lakes hydrologically connected to peatlands.     

The Delineation of a Point Source Plume by the Study of Bacterial Populations

Recent point source microbiological studies, using radial grid sampling stations, have indicated the potential of using bacterial populations to delineate mixing zones and identify the plumes. The discharge from the Niagara River into Lake Ontario was studied and microbiological data from the main plume area (impact zone), zone of minor influence of the plume, and the non-plume lake waters are presented. The microbiological observations were found to agree with thermal observations of the plume area made by remote sensing scanning techniques.     

Effects of Atrazine,Metolachlor, Carbaryl and Chlorothalonil on Benthic Microbes and Their Nutrient Dynamics

Atrazine, metolachlor, carbaryl, and chlorothalonil are detected in streams throughout the U.S. at concentrations that may have adverse effects on benthic microbes. Sediment samples were exposed to these pesticides to quantify responses of ammonium, nitrate, and phosphate uptake by the benthic microbial community. Control uptake rates of sediments had net remineralization of nitrate (−1.58 NO₃ µg gdm⁻¹ h⁻¹), and net assimilation of phosphate (1.34 PO₄ µg gdm⁻¹ h⁻¹) and ammonium (0.03 NH₄ µg gdm⁻¹ h⁻¹). Metolachlor decreased ammonium and phosphate uptake. Chlorothalonil decreased nitrate remineralization and phosphate uptake. Nitrate, ammonium, and phosphate uptake rates are more pronounced in the presence of these pesticides due to microbial adaptations to toxicants. Our interpretation of pesticide availability based on their water/solid affinities supports no effects for atrazine and carbaryl, decreasing nitrate remineralization, and phosphate assimilation in response to chlorothalonil. Further, decreased ammonium and phosphate uptake in response to metolachlor is likely due to affinity. Because atrazine target autotrophs, and carbaryl synaptic activity, effects on benthic microbes were not hypothesized, consistent with results. Metolachlor and chlorothalonil (non-specific modes of action) had significant effects on sediment microbial nutrient dynamics. Thus, pesticides with a higher affinity to sediments and/or broad modes of action are likely to affect sediment microbes'' nutrient dynamics than pesticides dissolved in water or specific modes of action. Predicted nutrient uptake rates were calculated at mean and peak concentrations of metolachlor and chlorothalonil in freshwaters using polynomial equations generated in this experiment. We concluded that in natural ecosystems, peak chlorothalonil and metolachlor concentrations could affect phosphate and ammonium by decreasing net assimilation, and nitrate uptake rates by decreasing remineralization, relative to mean concentrations of metolachlor and chlorothalonil. Our regression equations can complement models of nitrogen and phosphorus availability in streams to predict potential changes in nutrient dynamics in response to pesticides in freshwaters.     

Preparation,Characterization and Application of Magnetic Fe3O4-CS for the Adsorption of Orange I from Aqueous Solutions

Fe₃O₄ (Fe₃O₄-CS) coated with magnetic chitosan was prepared as an adsorbent for the removal of Orange I from aqueous solutions and characterized by FTIR, XRD, SEM, TEM and TGA measurements. The effects of pH, initial concentration and contact time on the adsorption of Orange I from aqueous solutions were investigated. The decoloration rate was higher than 94% in the initial concentration range of 50–150 mg L⁻¹ at pH 2.0. The maximum adsorption amount was 183.2 mg g⁻¹ and was obtained at an initial concentration of 400 mg L⁻¹ at pH 2.0. The adsorption equilibrium was reached in 30 minutes, demonstrating that the obtained adsorbent has the potential for practical application. The equilibrium adsorption isotherm was analyzed by the Freundlich and Langmuir models, and the adsorption kinetics were analyzed by the pseudo-first-order and pseudo-second-order kinetic models. The higher linear correlation coefficients showed that the Langmuir model (R² = 0.9995) and pseudo-second-order model (R² = 0.9561) offered the better fits.     

Exposure to Cerium Dioxide Nanoparticles Differently Affect Swimming Performance and Survival in Two Daphnid Species

The CeO₂ NPs are increasingly used in industry but the environmental release of these NPs and their subsequent behavior and biological effects are currently unclear. This study evaluates for the first time the effects of CeO₂ NPs on the survival and the swimming performance of two cladoceran species, Daphnia similis and Daphnia pulex after 1, 10 and 100 mg.L⁻¹ CeO₂ exposures for 48 h. Acute toxicity bioassays were performed to determine EC₅₀ of exposed daphnids. Video-recorded swimming behavior of both daphnids was used to measure swimming speeds after various exposures to aggregated CeO₂ NPs. The acute ecotoxicity showed that D. similis is 350 times more sensitive to CeO₂ NPs than D. pulex, showing 48-h EC₅₀ of 0.26 mg.L⁻¹ and 91.79 mg.L⁻¹, respectively. Both species interacted with CeO₂ NPs (adsorption), but much more strongly in the case of D. similis. Swimming velocities (SV) were differently and significantly affected by CeO₂ NPs for both species. A 48-h exposure to 1 mg.L⁻¹ induced a decrease of 30% and 40% of the SV in D. pulex and D. similis, respectively. However at higher concentrations, the SV of D. similis was more impacted (60% off for 10 mg.L⁻¹ and 100 mg.L⁻¹) than the one of D. pulex. These interspecific toxic effects of CeO₂ NPs are explained by morphological variations such as the presence of reliefs on the cuticle and a longer distal spine in D. similis acting as traps for the CeO₂ aggregates. In addition, D. similis has a mean SV double that of D. pulex and thus initially collides with twice more NPs aggregates. The ecotoxicological consequences on the behavior and physiology of a CeO₂ NPs exposure in daphnids are discussed.     

Biodegradation of Methyl tert-Butyl Ether by a Bacterial Pure Culture

A bacterial strain, PM1, which is able to utilize methyl tert-butyl ether (MTBE) as its sole carbon and energy source, was isolated from a mixed microbial consortium in a compost biofilter capable of degrading MTBE. Initial linear rates of MTBE degradation by 2 × 10⁶ cells ml⁻¹ were 0.07, 1.17, and 3.56 μg ml⁻¹ h⁻¹ for initial concentrations of 5, 50, and 500 μg MTBE ml⁻¹, respectively. When incubated with 20 μg of uniformly labeled [¹⁴C]MTBE ml⁻¹, strain PM1 converted 46% to ¹⁴CO₂ and 19% to ¹⁴C-labeled cells within 120 h. This yield is consistent with the measurement of protein accumulation at different MTBE concentrations from which was estimated a biomass yield of 0.18 mg of cells mg MTBE⁻¹. Strain PM1 was inoculated into sediment core material collected from a contaminated groundwater plume at Port Hueneme, California, in which there was no evidence of MTBE degradation. Strain PM1 readily degraded 20 μg of MTBE ml⁻¹ added to the core material. The rate of MTBE removal increased with additional inputs of 20 μg of MTBE ml⁻¹. These results suggest that PM1 has potential for use in the remediation of MTBE-contaminated environments.     

Establishment of an efficient and rapid method of multiple shoot regeneration and a comparative phenolics profile in in vitro and greenhouse-grown plants of psophocarpus tetragonolobus (L.) DC

An in vitro method of multiple shoot induction and plant regeneration in Psophocarpus tetragonolobus (L.) DC was developed. Cotyledons, hypocotyls, epicotyls, internodal and young seedling leaves were used as explants. MS media supplemented with various concentrations of either thidiazuron (TDZ) or N6-benzylaminopurine (BAP) along with NAA or IAA combinations were used to determine their influence on multiple shoot induction. MS media supplemented with TDZ induced direct shoot regeneration when epicotyls and internodal segments were used as explants. TDZ at 3 mg L⁻¹ induced highest rate (89.2 ± 3.28%) of regeneration with (13.4 ± 2.04) shoots per explant. MS media supplemented with BAP in combination with NAA or IAA induced callus mediated regeneration when cotyledons and hypocotyls were used as explants. BAP (2.5 mg L⁻¹) and IAA (0.2 mg L⁻¹) induced highest rate (100 ± 2.66%) of regeneration with (23.2 ± 2.66) shoots per explant. Mature plants produced from regenerated shoots were transferred successfully to the greenhouse. In a comparative study, the phenolics contents of various parts of greenhouse-grown plants with that of in vitro-raised plants showed significant variations.     

Metabolic Engineering of Rational Screened Saccharopolyspora spinosa for the Enhancement of Spinosyns A and D Production

Spinosyns A and D are potent ingredient for insect control with exceptional safety to non-target organisms. It consists of a 21-carbon tetracyclic lactone with forosamine and tri-O-methylated rhamnose which are derived from S-adenosylmethionine. Although previous studies have revealed the involvement of metK1 (S-adenosylmethionine synthetase), rmbA (glucose-1-phosphate thymidylyltransferase), and rmbB (TDP-D-glucose-4, 6-dehydratase) in the biosynthesis of spinosad, expression of these genes into rational screened Saccharopolyspora spinosa (S. spinosa MUV) has not been elucidated till date. In the present study, S. spinosa MUV was developed to utilize for metabolic engineering. The yield of spinosyns A and D in S. spinosa MUV was 244 mg L⁻¹ and 129 mg L⁻¹, which was 4.88-fold and 4.77-fold higher than that in the wild-type (50 mg L⁻¹ and 27 mg L⁻¹), respectively. To achieve the better production; positive regulator metK1-sp, rmbA and rmbB genes from Streptomyces peucetius, were expressed and co-expressed in S. spinosa MUV under the control of strong ermE* promoter, using an integration vector pSET152 and expression vector pIBR25, respectively. Herewith, the genetically engineered strain of S. spinosa MUV, produce spinosyns A and D up to 372/217 mg L⁻¹ that is 7.44/8.03-fold greater than that of wild type. This result demonstrates the use of metabolic engineering on rationally developed high producing natural variants for the production.     

Optimization of an improved,efficient and rapid in vitro micropropagation protocol for Petunia hybrida Vilm. Cv. “Bravo”

An efficient protocol for in-vitro propagation of an important ornamental crop, Petunia hybrida Vilm. Cv. “Bravo” was developed. The explants that were used to carry out the experiment were Leaf segments, nodal segments and shoot tips. Nodal segments recorded highest per cent asepsis followed by shoot tips and leaf segments. Asepsis was found to be highest when the explants were sterilized with Fungicide (Carbendazim) 0.02% for the duration of 30 min followed by 0.1% HgCl₂ for duration of 10 min and then ethanol 70% for 10 s. Longer duration of the sterilant treatment showed more necrotic effects on the explants, thus mercuric chloride treatment when given for 5 min proved to be more effective in terms of survival of the explants. Maximum establishment per cent was recorded in Murashige and Skoog (MS) media fortified with BAP (1.5 mg L⁻¹) and IBA (0.5 mg L⁻¹) in shoot tips and nodal segments, i.e. 97.90 and 95.74% respectively. Callus was efficiently induced and developed when PGR amalgamation of BAP (0.1 mg L⁻¹) and 2,4-D (1.5mg L⁻¹) was used. Kinetin at the concentration of 2.0 mg L⁻¹ along with IBA at 0.5mg L⁻¹ recorded highest callus regeneration in both leaf and internodal segment derived callus. Maximum proliferation percent of shoots (97.90%), highest number of shoots (20.50 explant⁻¹) and maximum length of shoot (2.70 cm) was recorded in PGR combination of IBA and BAP both at 0.5 mg L⁻1 concentration level. Rhizogenesis was recorded to be highest in the MS media containing IBA 1.00 mg L⁻¹. Best hardening media which recorded maximum survival per cent 92.50% was noticed on the media formulation comprised of equal ratio of perlite and vermiculite mix, under poly house conditions.     

Partial Optimization of the 5-Terminal Codon Increased a Recombination Porcine Pancreatic Lipase (opPPL) Expression in Pichia pastoris

Pancreatic lipase plays a key role in intestinal digestion of feed fat, and is often deficient in young animals such as weaning piglets. The objective of this study was to express and characterize a partial codon optimized porcine pancreatic lipase (opPPL). A 537 bp cDNA fragment encoding N-terminus amino acid residue of the mature porcine pancreatic lipase was synthesized according to the codon bias of Pichia pastoris and ligated to the full-length porcine pancreatic lipase cDNA fragment. The codon optimized PPL was cloned into the pPICZαA (Invitrogen, Beijing, China) vector. After the resultant opPPL/pPICZαΑ plasmid was transformed into P.pastoris, the over-expressed extracellular opPPL containing a His-tag to the C terminus was purified using Ni Sepharose affinity column (GE Healthcare, Piscataway, NJ, USA), and was characterized against the native enzyme (commercial PPL from porcine pancreas, Sigma). The opPPL exhibited a molecular mass of approximately 52 kDa, and showed optimal temperature (40°C), optimal pH (8.0), K_m (0.041 mM), and V_max (2.008 µmol.mg protein ⁻¹.min⁻¹) similar to those of the commercial enzyme with p-NPP as the substrate. The recombinant enzyme was stable at 60°C, but lost 80% (P<0.05) of its activity after exposure to heat ≥60°C for 20 min. The codon optimization increased opPPL yield for ca 4 folds (146 mg.L⁻¹ vs 36 mg.L⁻¹) and total enzyme activity increased about 5 folds (1900 IU.L⁻¹ vs 367 IU.L⁻¹) compared with those native naPPL/pPICZαΑ tranformant. Comparison of gene copies and mRNA profiles between the two strains indicated the increased rePPL yields may partly be ascribed to the increased protein translational efficiency after codon optimization. In conclusion, we successfully optimized 5-terminal of porcine pancreatic lipase encoding gene and over-expressed the gene in P. pastoris as an extracellular, functional enzyme. The recombination enzyme demonstrates a potential for future use as an animal feed additive for animal improvement.     

IL-2 Regulates SEB Induced Toxic Shock Syndrome in BALB/c Mice

Background

Toxic Shock Syndrome (TSS) is characterized by fever, rash, hypotension, constitutional symptoms, and multi-organ involvement and is caused by Staphylococcus aureus enterotoxins such as Staphylococcal Enterotoxin B (SEB). SEB binds to the MHC-IIα chain and is recognized by the TCRβ chain of the Vβ8 TCR⁺ T cells. The binding of SEB to Vβ chain results in rapid activation of T cells and production of inflammatory cytokines, such as Interleukin-2 (IL-2), Interferon-γ and Tumor Necrosis Factor-α which mediate TSS. Although IL2 was originally identified as the T cell growth factor and was proposed to contribute to T cell differentiation, its role in TSS remains unexplored.

Methodology/Principal Findings

Mice were injected with D-Gal (25 mg/mouse). One hour after D-Galactosamine (D-Gal) injection each mouse was injected with SEB (20 µg/mouse. Mice were then observed for 72 hrs and death was recorded at different times. We tested Interleukin-12, IFNγ, and IL-2 deficient mice (IL-2^−/−), but only the IL-2 deficient mice were resistant to SEB induced toxic shock syndrome. More importantly reconstitution of IL-2 in IL-2 deficient mice restored the shock. Interestingly, SEB induced IL-2 production from T cells was dependent on p38MAPK activation in macrophages as inhibition of it in macrophages significantly inhibited IL-2 production from T cells.

Conclusion

This study shows the importance of IL -2 in TSS which has not been previously explored and it also shows that regulating macrophages function can regulate T cells and TSS.     

Improvement of efficient in vitro regeneration potential of mature callus induced from Malaysian upland rice seed (Oryza sativa cv. Panderas)

A new and rapid protocol for optimum callus production and complete plant regeneration has been assessed in Malaysian upland rice (Oryza sativa) cv. Panderas. The effect of plant growth regulator (PGR) on the regeneration frequency of Malaysian upland rice (cv. Panderas) was investigated. Mature seeds were used as a starting material for callus induction experiment using various concentrations of 2,4-D and NAA. Optimal callus induction frequency at 90% was obtained on MS media containing 2,4-D (3 mg L⁻¹) and NAA (2 mg L⁻¹) after 6 weeks while no significant difference was seen on tryptophan and glutamine parameters. Embryogenic callus was recorded as compact, globular and light yellowish in color. The embryogenic callus morphology was further confirmed with scanning electron microscopy (SEM) analysis. For regeneration, induced calli were treated with various concentrations of Kin (0.5–1.5 mg L⁻¹), BAP, NAA and 0.5 mg L⁻¹ of TDZ. The result showed that the maximum regeneration frequency (100%) was achieved on MS medium containing BAP (0.5 mg L⁻¹), Kin (1.5 mg L⁻¹), NAA (0.5 mg L⁻¹) and TDZ (0.5 mg L⁻¹) within four weeks. Developed shoots were successfully rooted on half strength MS free hormone medium and later transferred into a pot containing soil for acclimatization. This cutting-edge finding is unique over the other existing publishable data due to the good regeneration response by producing a large number of shoots.Abbreviations: 2,4-D, 2,4-dichlorophenoxyacetic acid; NAA, naphthaleneacetic acid; Kin, kinetin; MS, Murashige and Skoog; BAP, benzylaminopurine; TDZ, thidiazuron     

The Interaction of Large Amplitude Internal Seiches with a Shallow Sloping Lakebed: Observations of Benthic Turbulence in Lake Simcoe,Ontario, Canada

Observations of the interactions of large amplitude internal seiches with the sloping boundary of Lake Simcoe, Canada show a pronounced asymmetry between up- and downwelling. Data were obtained during a 42-day period in late summer with an ADCP and an array of four thermistor chains located in a 5 km line at the depths where the thermocline intersects the shallow slope of the lakebed. The thermocline is located at depths of 12–14 m during the strongly stratified period of late summer. During periods of strong westerly winds the thermocline is deflected as much as 8 m vertically and interacts directly with the lakebed at depth between 14–18 m. When the thermocline was rising at the boundary, the stratification resembles a turbulent bore that propagates up the sloping lakebed with a speed of 0.05–0.15 m s⁻¹ and a Froude number close to unity. There were strong temperature overturns associated with the abrupt changes in temperature across the bore. Based on the size of overturns in the near bed stratification, we show that the inferred turbulent diffusivity varies by up to two orders of magnitude between up- and downwellings. When the thermocline was rising, estimates of turbulent diffusivity were high with K_Z ∼10⁻⁴ m²s⁻¹, whereas during downwelling events the near-bed stratification was greatly increased and the turbulence was reduced. This asymmetry is consistent with previous field observations and underlines the importance of shear-induced convection in benthic bottom boundary layers of stratified lakes.     

Application of Molecularly Imprinted Polymers to Selective Removal of Clofibric Acid from Water

A new molecularly imprinted polymer (MIP) adsorbent for clofibric acid (CA) was prepared by a non-covalent protocol. Characterization of the obtained MIP was achieved by scanning electron microscopy (SEM) and nitrogen sorption. Sorption experimental results showed that the MIP had excellent binding affinity for CA and the adsorption of CA by MIP was well described by pseudo-second-order model. Scatchard plot analysis revealed that two classes of binding sites were formed in the MIP with dissociation constants of 7.52±0.46 mg L⁻¹ and 114±4.2 mg L⁻¹, respectively. The selectivity of MIP demonstrated higher affinity for CA over competitive compound than that of non-imprinted polymers (NIP). The MIP synthesized was used to remove CA from spiked surface water and exhibited significant binding affinity towards CA in the presence of total dissolved solids (TDS). In addition, MIP reusability was demonstrated for at least 12 repeated cycles without significant loss in performance.