Dimethylsulphopropionate (DMSP) and proline from the surface of the brown alga Fucus vesiculosus inhibit bacterial attachment

It was demonstrated previously that polar and non-polar surface extracts of the brown alga Fucus vesiculosus collected during winter from the Kiel Bight (Germany) inhibited bacterial attachment at natural concentrations. The present study describes the bioassay-guided identification of the active metabolites from the polar fraction. Chromatographic separation on a size-exclusion liquid chromatography column and bioassays identified an active fraction that was further investigated using nuclear magnetic resonance spectroscopy and mass spectrometry. This fraction contained the metabolites dimethylsulphopropionate (DMSP), proline and alanine. DMSP and proline caused the anti-attachment activity. The metabolites were further quantified on the algal surface together with its associated boundary layer. DMSP and proline were detected in the range 0.12–1.08 ng cm^?2 and 0.09–0.59 ng cm^?2, respectively. These metabolites were tested in the concentration range from 0.1 to 1000 ng cm^?2 against the attachment of five bacterial strains isolated from algae and sediment co-occurring with F. vesiculosus. The surface concentrations for 50% inhibition of attachment of these strains were always <0.38 ng cm^?2 for DMSP and in four cases <0.1 ng cm^?2 for proline, while one strain required 1.66 ng cm^?2 of proline for 50% inhibition. Two further bacterial strains that had been directly isolated from F. vesiculosus were also tested, but proved to be the least sensitive. This study shows that DMSP and proline have an ecologically relevant role as surface inhibitors against bacterial attachment on F. vesiculosus.     

Toxicity of 2,3,5,6-tetrachlorophenol to willow trees (Salix viminalis)

Chlorinated phenols have been intensively investigated from an eco-toxicological point of view, however almost nothing is known about toxicity of tetrachlorophenol (TeCP) to higher terrestrial plants. This article applied the willow tree acute toxicity test to study the toxicity of 2,3,5,6-TeCP to willows Salix viminalis (S. viminalis) at neutral and acidic conditions (roughly pH 7 and 4) with inhibition of transpiration as toxic endpoint. At neutral pH the EC₅₀ was >10 mg L^?1 while the EC₅₀ at acidic conditions was 0.32 ± 0.17 mg L^?1, clearly indicating that toxicity is exerted by the non-ionic chemical fraction. Standard tests running at neutral pH are therefore not capturing the full toxicity of weak acids and bases.     

Acute toxicity of nitrite in fat snook (Centropomus parallelus)

Oxidative stress and hypoxia responses in Centropomus parallelus exposed to three different concentrations of nitrite (0, 0.5, and 10 mg L^?1) were evaluated. To determinate toxicity, we used enzymatic analyses and quantifications of oxygen consumption and opercular beats under conditions of normoxia and hypoxia. There was no significant difference in GST, CAT, or GPx enzymes in the liver or in GPx in the gills. Levels of GST were altered at a concentration of 10 mg L^?1 in experiment I. Experiment II displayed alterations for GST and CAT in the liver at the same concentration, indicating that exposure to nitrite does not generate differentiated activation in the body’s defense system by the production of oxidative stress enzymes. When nitrite was associated with hypoxia, there was a significant increase in both enzymatic activity and opercular beating under hypoxia in the group exposed to 10 mg L^?1 nitrite compared to the control.     

Acute toxicity of ammonia and nitrite to different ages of Pacific cod (Gadus macrocephalus) larvae

Abstract

This study was conducted to evaluate the acute toxicity of ammonia and nitrite to three developmental stages of Pacific cod (Gadus macrocephalus) larvae (11, 22, and 35 days after hatching, with mean total lengths of 4.63 ± 0.14, 5.83 ± 0.17, and 7.46 ± 0.23 mm, respectively). The results showed for the first time that the acute toxicity of ammonia and nitrite is closely related to the age of Pacific cod larvae, and the acute toxicity of ammonia or nitrite increased with increased Pacific cod larval growth. Lethal concentrations (LC₅₀) of un-ionized ammonia nitrogen (UIAN) for a 48-h exposure in 11-day post-hatch, 22-day post-hatch, and 35-day post-hatch Pacific cod larvae were 1.72, 0.69, and 0.32 mg L^?1, respectively. The 48-h LC₅₀ of nitrite nitrogen to Pacific cod larvae 11-day post-hatch, 22-day post-hatch, and 35-day post-hatch were 831.76, 269.15, and 223.87 mg L^?1, respectively. The present findings demonstrate that the acute toxicity of ammonia for Pacific cod larvae is much higher than that of nitrite.     

Distribution of surface soil mercury of Wuda old mining area,Inner Mongolia,China

In this study, mercury (Hg) concentrations in dustfall and topsoil were investigated. Three hundred forty-four samples were collected, including dustfall and topsoil samples, across an area of ～180 km² in Wuda, China. Dustfall Hg concentration in Wuda ranged from 10 to 6453 ng·g^?1_, with an average of 305 ng·g^?1, and topsoil Hg concentration ranged from 3 to 1537 ng·g^?1, with an average value of 135 ng·g^?1. The average dustfall Hg concentrations in the coalfield, industrial park, and urban areas were 289 ng·g^?1, 809 ng·g^?1, and 160 ng·g^?1, respectively, and the corresponding average topsoil Hg concentrations were 216 ng·g^?1, 242 ng·g^?1, and 91 ng·g^?1. Hg concentrations were significantly higher in the coalfield, industrial park, and urban areas compared with background values for Wuda and China tide soil. The coal Hg concentrations ranged from 273 to 346 ng·g^?1, with an average value of 317 ng·g^?1. Comparison of the Hg concentrations of Wuda coal with other regions and countries, indicated that Hg concentrations were significantly enriched in coal, highlighting that coal is the primary Hg source for Wuda District. While coal fires provided the primary source of Hg, some higher Hg values were caused by factors such as gangue hills and coalfield topography, the use of activated carbon with HgCl₂ as a catalyst in the industrial park, and several coal washeries in wasteland areas. In addition to atmospheric Hg, underground coal seam emissions served as another potential Hg source in the coalfield. The surface soil Hg in the coalfield and industrial park areas should be given closer attention in the future.     

Phytoremediation of wastewater toxicity using water hyacinth (Eichhornia crassipes) and water lettuce (Pistia stratiotes)

This paper elucidates the phytoremediation potential of water hyacinth and water lettuce on the reduction of wastewater toxicity. Acute toxicity tests were performed in an aquarium with a population of Sarotherodon melanotheron, contaminated by different concentrations of wastewaters before and after phytoremediation with Eichhornia crassipes and Pistia stratiotes. Lethal concentrations (LC₅₀) of the fish's population obtained during 24 hours of exposures were determined. COD, BOD, ammonium, TKN and PO₄^3? concentrations in wastewaters were of 1850.29, 973.33, 38.34, 61.49 and 39.23 mg L^?1, respectively, for each plant. Phytoremediation reduced 58.87% of ammonium content, 50.04% of PO₄^3?, 82.45% of COD and 84.91% of BOD. After 15 days of the experiment, metal contents in treated wastewaters decreased from 6.65 to 97.56% for water hyacinth and 3.51 to 93.51% for water lettuce tanks. Toxicity tests showed that the mortality of fish exposed increased with increase in concentration of pollutants in wastewaters and the time of exposure. Therefore, the highest value of LC₅₀ was recorded for fish subjected to 3 hours of exposure (16.37%). The lowest rate was obtained after an exposure of 20 to 24 hours (5.85%). After phytoremediation, the effluents purified by Eichhornia crassipes can maintain the fish life beyond 24 hours of exposure.     

Influence of the Freeze-Drying Process on the Physicochemical and Biological Properties of Pre-heated Amphotericin B Micellar Systems

The moderate heat treatment of amphotericin B (AmB) in its micellar form (M-AmB) results in superaggregates (H-AmB) that present a substantially lower toxicity and similar activity. The aim of this work was to evaluate the H-AmB behavior after a freeze-drying process. H-AmB and M-AmB micelles were evaluated before and after freeze-drying concerning their physicochemical and biological properties by spectrophotometry and activity/toxicity assay, respectively. Four concentrations of M-AmB and H-AmB were studied aiming to correlate their aggregation state and the respective biological behavior: 50 mg L^?1, 5 mg L^?1, 0.5 mg L^?1, and 0.05 mg L^?1. Then, potassium leakage and hemoglobin leakage from red blood cells were used to evaluate the acute and chronic toxicity, respectively. The efficacy of M-AmB and H-AmB formulations was assessed by potassium leakage from Candida albicans and by the broth microdilution method. After heating, in addition to an evident turbidity, a slight blueshift from 327 to 323 nm was also observed at the concentrations of 50 and 5 mg L^?1 for H-AmB. Additionally, an increase in the absorbance at 323 nm at the concentration of 0.5 mg L^?1 was detected. Concerning the toxicity, H-AmB caused significantly lower hemoglobin leakage than M-AmB. These results were observed for H-AmB before and after freeze-drying. However, there was no difference between H-AmB and M-AmB concerning their activity. Accordingly, the freeze-drying cycle did not show any influence on the behavior of heated formulations, highlighting the suitability of such a method to produce a new AmB product with a long shelf life and with both greater efficiency and less toxicity.     

A microcosm investigation of fe (iron) removal using macrophytes of ramsar lake: A phytoremediation approach

The present study deals with the microcosm study of Fe (Iron) phytoremediation using Eichhornia crassipes, Lemna minor, Pistia stratiotes and Salvinia cucullata species collected from the Loktak Lake, a Ramsar Site which exists in north-eastern India (an Indo-Burma hotspot region). Efficiency of these four macrophytes was compared using different Fe concentrations of 1 mg L^?1, 3 mg L^?1 and 5 mg L^?1 for 4 days, 8 days and 12 days, respectively. E. crassipes was the most efficient macrophyte whereas L. minor was the least efficient. E. crassipes removed the highest percentage of Fe, i.e. 89% from 1 mg L^?1, 81.3% from 3 mg L^?1 and 73.2% from 5 mg L^?1 in 12-day experiment.     

CITRIC ACID PRODUCTION BY Candida SPECIES GROWN ON A SOY-BASED CRUDE GLYCEROL

Citric acid was produced by five species of the yeast Candida after growth on a medium containing soy biodiesel-based crude glycerol. After growth on a medium containing 10 g L^?1 or 60 g L^?1 crude glycerol for 168 hr at 30°C, Candida parapsilosis ATCC 7330 and C. guilliermondii ATCC 9058 produced the highest citric acid levels. On 10 g L^?1 or 60 g L^?1 crude glycerol for 168 hr at 30°C, the citric acid level produced by C. parapsilosis ATCC 7330 was 1.8 g L^?1 or 11.3 g L^?1, respectively, while C. guilliermondii ATCC 9058 produced citric acid concentrations of 3.0 g L^?1 or 10.4 g L^?1, respectively. Biomass production by C. guilliermondii ATCC 9058 on 10 g L^?1 or 60 g L^?1 crude glycerol for 168 hr at 30°C was highest at 1.2 g L^?1 or 6.9 g L^?1, respectively. The citric acid yields observed for C. guilliermondii ATCC 9058 after growth on 10 g L^?1 or 60 g L^?1 crude glycerol (0.35 g g^?1 or 0.21 g g^?1, respectively) were generally higher than for the other Candida species tested. When similar crude glycerol concentrations were present in the culture medium, citric acid yields observed for some of the Candida species utilized in this study were about the same or higher compared to citric acid yields by Yarrowia lipolytica strains. Based on the findings, it appeared that C. guilliermondii ATCC 9058 was the most effective species utilized, with its citric acid production being similar to what has been observed when citric acid-producing strains of Y. lipolytica were grown on crude glycerol under batch conditions that could be of significance to biobased citric acid production.     

Various effects of ethanolic extract of Mentha pulegium on the two-spotted spider mite,Tetranychus urticae (Tetranychidae)

Ethanolic extract of Mentha pulegium was evaluated against the adults of important arthropod pest species, the two-spotted spider mite, Tetranychus urticae. Potential acaricidal impact of plant was determined by contact application. Phytotoxicity was recorded after 24 h. The value of LC₅₀ was 59,149 mg L^?1. Also, LT₅₀ values were 27.42, 25.56 and 19.79 h for 35,000, 50,000 and 100,000 mg L^?1, respectively. Also, results showed that this ethanolic extract had impact on repellency of T. urticae. All of the tested concentrations were similar in the repellency test. On the other hand, the used concentrations (1000, 4000, 6000 and 8000 mg L^?1) affected on the oviposition of mite females. These extract doses significantly decreased the egg laying on the treated surface. The current study indicated that this ethanolic extract can be used as a safe acaricide on T. urticae.     

Enhancing of Phytoremediation Efficiency Using Indole-3-Acetic Acid (IAA)

In this study, a pot experiment using Solanum nigrum L. grown in cadmium-contaminated soil was conducted in a greenhouse. Indole-3-acetic acid (IAA) was applied at three different concentrations (1 mg L^?1, 10 mg L^?1, and 100 mg L^?1) to examine the effects on phytoremediation efficiency. According to the experimental results, IAA increased the shoot biomass of S. nigrum significantly, by 124% at the highest concentration used, and increased the Cd concentration in the shoot of S. nigrum by 16%. The Cd extraction amount from a single plant was increased by up to 158%, demonstrating potential practical application for remediation practice.     

Occurrence and levels of pesticides in South Lebanon water

This study reviews the detection of pesticides in different surface and groundwater samples collected from South Litani region in South Lebanon during 2012. These have been analyzed using an optimized and validated solid phase extraction method followed by gas chromatography coupled with mass spectrometry. Organochlorine and organophosphate pesticides were mostly noted at levels below the recommended value for individual pesticide in water except pirimiphos-methyl that was recorded at 300.87 ng L^?1 in groundwater sample, designated for drinking water and collected in February. DDE concentration exceeded 100 ng L^?1 in both surface and groundwater in October. The reported results represent the first Lebanese statistical data illustrating the quantification of pesticides in water over a period of time. More importantly, it draws attention to the need of pesticides’ monitoring programs in the Lebanese water resources.     

The system modulating ROS content in germinating seeds of two Brazilian savanna tree species exposed to As and Zn

The effects of increasing arsenic (0, 10, 50, 100 mg L^?1) and zinc (0, 50, 80, 120, 200 mg L^?1) doses on germination and oxidative stress markers (H₂O₂, MDA, SOD, CAT, APX, and GR) were examined in two Brazilian savanna tree species (Anadenanthera peregrina and Myracrodruon urundeuva) commonly used to remediate contaminated soils. The deleterious effects of As and Zn on seed germination were due to As- and Zn-induced H₂O₂ accumulation and inhibition of APX and GR activities, which lead to oxidative damage by lipid peroxidation. SOD and CAT did not show any As- and Zn-induced inhibition of their activities as was seen with APX and GR. We investigated the close relationships between seed germination success under As and Zn stress in terms of GR and, especially, APX activities. Increased germination of A. peregrina seeds exposed to 50 mg L^?1 of Zn was related to increased APX activity, and germination in the presence of As (10 mg L^?1) was observed only in M. urundeuva seeds that demonstrated increased APX activity. All the treatments for both species in which germination decreased or was inhibited showed decreases in APX activity. A. peregrina seeds showed higher Zn-tolerance than M. urundeuva, while the reverse was observed with arsenic up to exposures of 10 mg L^?1.     

Enhancing ethanol production from cellulosic sugars using <Emphasis Type="Italic">Scheffersomyces (Pichia) stipitis</Emphasis>

Studies were performed on the effect of CaCO₃ and CaCl₂ supplementation to fermentation medium for ethanol production from xylose, glucose, or their mixtures using Scheffersomyces (Pichia) stipitis. Both of these chemicals were found to improve maximum ethanol concentration and ethanol productivity. Use of xylose alone resulted in the production of 20.68 ± 0.44 g L^?1 ethanol with a productivity of 0.17 ± 0.00 g L^?1 h^?1, while xylose plus 3 g L^?1 CaCO₃ resulted in the production of 24.68 ± 0.75 g L^?1 ethanol with a productivity of 0.21 ± 0.01 g L^?1 h^?1. Use of xylose plus glucose in combination with 3 g L^?1 CaCO₃ resulted in the production of 47.37 ± 0.55 g L^?1 ethanol (aerobic culture), thus resulting in an ethanol productivity of 0.39 ± 0.00 g L^?1 h^?1. These values are 229 % of that achieved in xylose medium. Supplementation of xylose and glucose medium with 0.40 g L^?1 CaCl₂ resulted in the production of 44.84 ± 0.28 g L^?1 ethanol with a productivity of 0.37 ± 0.02 g L^?1 h^?1. Use of glucose plus 3 g L^?1 CaCO₃ resulted in the production of 57.39 ± 1.41 g L^?1 ethanol under micro-aerophilic conditions. These results indicate that supplementation of cellulosic sugars in the fermentation medium with CaCO₃ and CaCl₂ would improve economics of ethanol production from agricultural residues.     

Morphophysiological,ultrastructural, and nutritional changes induced by Cu toxicity in young Erythrina fusca plants

Erythrina fusca is an important legume used for shade cover in cacao plantations in Brazil. Cacao plantations receive large quantities of copper (Cu)-containing agrochemicals, mainly for control of diseases. Therefore, Cu toxicity was investigated in seedlings grown in hydroponics with increasing concentrations of Cu (0.005–32 mg L^?1) in a greenhouse. Ultrastructural analyses showed cell plasmolysis in the root cortical area and changes in thylakoid membranes at 8 mg Cu L^?1 and higher. There were changes in epicuticular wax deposition on the leaf surface at the 16 and 32 mg Cu L^?1 treatments. Leaf gas exchanges were highly affected 24 hours after application of treatments beginning at 8 mg Cu L^?1 and higher Cu concentrations. Chemical analyses showed that Cu content in E. fusca roots increased as Cu concentration in the nutrient solution increased, whereas the shoot did not show significant changes. It is also observed that excess Cu interfered with Zn, Fe, Mn, Mg, K, P, and Ca content in the different E. fusca organs. Investigation of Cu toxicity symptoms focusing on morphophysiological, ultrastructural, gas exchange, and nutritional changes would be useful to alleviate Cu toxicity in E. fusca under field conditions, an important agroforestry species in cacao plantation.     

Effects of indole-3-acetic acid on arsenic uptake and antioxidative enzymes in Pteris cretica var. nervosa and Pteris ensiformis

A hydroponic experiment was conducted to investigate the effects of indole-3-acetic acid (IAA) on arsenic (As) uptake and antioxidative enzymes in fronds of Pteris cretica var. nervosa (As hyperaccumulator) and Pteris ensiformis (non-hyperaccumulator). Plants were exposed to 2 mg L^?1 As(III), As(V) or dimethylarsinic acid (DMA) and IAA concentrations for 14 d. The biomass and total As in the plants significantly increased at 30 mg L^?1 IAA. Superoxide dismutase (SOD) activities significantly increased with IAA addition. Catalase (CAT) activities showed a significant increase in P. ensiformis exposed to three As species at 30 or 50 mg L^?1 IAA but varied in P. cretica var. nervosa. Peroxidase (POD) activities were unchanged in P. ensiformis except for a significant decrease at 50 mg L^?1 IAA under As(III) treatment. However, a significant increase was observed in P. cretica var. nervosa at 10 mg L^?1 IAA under As(III) or DMA treatment and at 50 mg L^?1 IAA under As(V) treatment. Under DMA stress, malondialdehyde contents in fronds of P. cretica var. nervosa showed a significant decrease at 10 mg L^?1 IAA but remained unchanged in P. ensiformis. Therefore, IAA enhanced As uptake and frond POD activity in P. cretica var. nervosa under As stress.     

Cadmium Dynamics in the Rhizosphere and Cd Uptake of Different Plant Species Evaluated by A Mechanistic Model

Maize, sunflower, flax, and spinach differed in the accumulation of Cd when grown on a Cd contaminated soil. This was mainly due to the different Cd net influx, I_n , that varied among species by a factor of up to 30. The objective of this study was to find possible reasons for the different Cd I_n by using a mechanistic model. After 14 days of Cd uptake the model calculated only a small Cd depletion at the root surface, e.g. from 0.22 μmol L^?1down to 0.19 μmol L^?1for maize and from 0.48 μmol L^?1down to 0.35 μmol L^?1for spinach. Even so the model always overestimated the Cd I_n , for spinach by a factor of 1.5 and for maize by a factor of 10. Only simulating a decrease of C_Li or the root absorbing power, α, by 40% to 90% gave an agreement of calculated and measured I_n . This may be interpreted as that about 40% in the case of spinach and 90% in the case of maize of the Cd in soil solution were not accessible for plant uptake. The high sensitivity to α also shows that not the Cd transport to the root but α was limiting the step for Cd uptake.     

Optimization of culture conditions for the production of polysaccharides and kinsenoside from the rhizome cultures of <Emphasis Type="Italic">Anoectochilus roxburghii</Emphasis> (Wall.) Lindl.

The present study designed two sets of experiments by using the uniform design method and investigated the effects of medium components on the accumulation of bioactive compounds (polysaccharide and kinsenoside) in rhizomes, in order to select a suitable culture medium for the rhizome suspension culture of Anoectochilus roxburghii (Wall.) Lindl. Among the combinations of Murashige and Skoog (MS) medium strengths and plant growth regulator (benzylaminopurine, BA; kinetin, KT; and α-naphthaleneacetic acid, NAA) concentrations, and the combinations of nitrogen, phosphorus, and sucrose concentrations, the maximum yield of polysaccharides and kinsenoside was achieved with 0.75 × MS?+?2.0 mg L^?1 BA?+?0.2 mg L^?1 KT?+?0.5 mg L^?1 NAA and 45 mM nitrogen?+?0.93 mM phosphorus?+?35 g L^?1 sucrose, respectively. Therefore, the optimal rhizome suspension culture medium was 0.75 × MS medium supplemented with 2.0 mg L^?1 BA, 0.2 mg L^?1 KT, 0.5 mg L^?1 NAA, and 35 g L^?1 sucrose. Yeast extract (YE) enhanced bioactive compound accumulation in rhizomes. The polysaccharide and kinsenoside production was significantly improved when 75 mg L^?1 YE was added to the culture medium after 30 d of rhizome suspension culture; 8.3 g L^?1 of polysaccharide and 6.1 g L^?1 of kinsenoside were obtained after 4 d of YE treatment. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of YE-treated rhizomes was higher than that of YE-untreated rhizomes, demonstrating enhanced antioxidant activity of the treated bioreactor-cultured rhizomes.     

Phytoextraction potential of water fern (Azolla pinnata) in the removal of a hazardous dye,methyl violet 2B: Artificial neural network modelling

This study investigated the potential of Azolla pinnata (AP) in the removal of toxic methyl violet 2B (MV) dye wastewater using the phytoextraction approach with the inclusion of an Artificial Neural Network (ANN) modelling. Parameters examined included the effects of dye concentration, pH and plant dosage. The highest removal efficiency was 93% which was achieved at a plant dosage of 0.8 g (dye volume = 200 mL, initial pH = 6.0, initial dye concentration = 10 mg L^?1). A significant decrease in relative frond number (RFN), a growth rate estimator, observed at a dye concentration of 20 mg L^?1 MV indicated some toxicity, which coincided with the plant pigments studies where the chlorophyll a content was lower than the control. There were little differences in the plant pigment contents between the control and those in the presence of dye (5 to 15 mg L^?1) indicating the tolerance of AP to MV at lower concentrations. A three-layer ANN model was optimized (6 neurons in the hidden layer) and successfully predicted the phytoextraction of MV (R = 0.9989, RMSE = 0.0098). In conclusion, AP proved to be a suitable plant that could be used for the phytoextraction of MV while the ANN modelling has shown to be a reliable method for the modelling of phytoextraction of MV using AP.     

Determination of the Superoxide Dismutase-Like Activity of Cimetidine-Cu(II) Complexes

Using the direct method of pulse radiolysis to determine the superoxide dismutase like activity of copper(II) cimetidine complexes, it was found that the reaction rate constant with O^?₂, k_cat, was (8.5 ± 0.5) × 10⁸ M^?1s^?1 independent of the cimetidine concentrations present in excess of 50–200 μM over the metal. The results suggest that either the 1:1 ligand to metal complex does not catalyze O^?₂ dismutation at a comparable rate to that of the 2:1 complex, or that the stability constant of the last species is much higher than that determined earlier by Kimura el al.,¹ and only the 2:1 species is present in the solutions. With the indirect methods of cytochrome c and NBT for determining the ability of these complexes to catalyze O^?₂ dismutation, these compounds exhibited a much lower SOD activity. and k_cat was determined to be (5.0 ± 0.3) × 10⁶ and (7.± 0.4) × 10¹ M^?1s^?1. respectively using the two assays.