Copper regulation and homeostasis of Daphnia magna and Pseudokirchneriella subcapitata: influence of acclimation

This study aimed to evaluate (1) the capacity of the green alga Pseudokirchneriella subcapitata and the waterflea Daphnia magna to regulate copper when exposed to environmentally realistic copper concentrations and (2) the influence of multi-generation acclimation to these copper concentrations on copper bioaccumulation and homeostasis. Based on bioconcentration factors, active copper regulation was observed in algae up to 5 microg Cu L(-1) and in daphnids up to 35 mug Cu L(-1). Constant body copper concentrations (13+/-4 microg Cu g DW(-1)) were observed in algae exposed to 1 through 5 microg Cu L(-1) and in daphnids exposed to 1 through 12 microg Cu L(-1). At higher exposure concentrations, there was an increase in internal body copper concentration, while no increase was observed in bioconcentration factors, suggesting the presence of a storage mechanism. At copper concentrations of 100 microg Cu L(-1) (P. subcapitata) and 150 microg Cu L(-1) (D. magna), the significant increases observed in body copper concentrations and in bioconcentration factors may be related to a failure of this regulation mechanism. For both organisms, internal body copper concentrations lower than 13 microg Cu g DW(-1) may result in copper deficiency. For P. subcapitata acclimated to 0.5 and 100 microg Cu L(-1), body copper concentrations ranged (mean+/-standard deviation) between 5+/-2 microg Cu g DW(-1) and 1300+/-197 microg Cu g DW(-1), respectively. For D. magna, this value ranged between 9+/-2 microg Cu g DW(-1) and 175+/-17 microg Cu g DW(-1) for daphnids acclimated to 0.5 and 150 microg Cu L(-1). Multi-generation acclimation to copper concentrations >or =12 microg Cu L(-1) resulted in a decrease (up to 40%) in body copper concentrations for both organisms compared to the body copper concentration of the first generation. It can be concluded that there is an indication that P. subcapitata and D. magna can regulate their whole body copper concentration to maintain copper homeostasis within their optimal copper range and acclimation enhances these mechanisms.     

Effects of the parasiticide ivermectin on the cladoceran Daphnia magna and the green alga Pseudokirchneriella subcapitata

Although widely used for the treatment of endo- and ectoparasites in livestock and pets, very few data on chronic effects on aquatic organisms are available for the parasiticide ivermectin. In the present study, toxicity of ivermectin to two freshwater organisms, the cladoceran Daphnia magna and the green alga Pseudokirchneriella subcapitata was investigated. For D. magna, a mean LC(50) 48 h of 5.7 ngl(-1) was derived from 10 acute tests. Chronic toxicity of ivermectin to D. magna was extremely high: with 0.001 and 0.0003 ngl(-1), respectively, nominal LOEC and NOEC based on growth and reproduction were far below the analytical limit of detection for this compound. P. subcapitata was considerably less sensitive to ivermectin than D. magna. For both growth rate and yield, EC(50) was >4,000 microgl(-1), LOEC was 1,250 microgl(-1) and NOEC 391microgl(-1). In view of the high toxicity to D. magna, the use of ivermectin might pose a risk to local aquatic ecosystems. Further studies should be carried out to investigate the effects of ivermectin and its degradation products on pelagic and benthic freshwater invertebrates.     

Influence of humic substances on the toxic effects of cadmium and zinc to the green alga Pseudokirchneriella subcapitata

A method combining (1 h) algal photosynthesis inhibition tests and tangential-flow ultrafiltration (TFF) technique (cut-off 1 kDa) was used to determine the effect of humic substances (HS) on acute metal toxicity to Pseudokirchneriella subcapitata. Three "standard" HS (soil and peat humic acids and Suwannee River fulvic acids) at two concentrations (1 and 5 mg/l) and two metals (Zn at 390 microg/l and Cd at 200 microg/l) were studied. Toxicity of Cd and Zn to P. subcapitata was significantly (p<0.05) reduced in the presence of humic acids (HA) but not in the presence of Suwannee River fulvic acids (SRFA). Metal partitioning between colloidal (1 microm-1 kDa) and truly dissolved (<1 kDa) fractions was found to match a decrease of metal toxicity in the presence of HA, but not in the presence of SRFA. The results suggested that HA reduced Cd and Zn toxicity in two different ways: (1) HA decrease the amount of free metal ions. Metal-HA complexes are high molecular weight, relatively stable with regard to metal-exchange reactions and consequently the metals were less bioavailable. (2) HA adsorbed onto algal surfaces, shielded the cells from free Cd and Zn ions. Several possible explanations can be postulated to account for the observed SRFA results: (1) Cd- and Zn-SRFA complexes are thought to be labile (i.e. undergo rapid dissociation); (2) SRFA coagulated, presumably during equilibration, and that coagulation altered metal complexing behavior of SRFA; (3) FA has a lower ability to adsorb on cell membranes at pH>7.     

Toxicity of surfactants to green microalgae Pseudokirchneriella subcapitata and Scenedesmus subspicatus and to marine diatoms Phaeodactylum tricornutum and Skeletonema costatum

Ecotoxicity of different commercial surfactants (six anionic, two amphoteric and one nonionic), essential constituents of cleansing hair products (shampoos), as well as ecotoxicity of eight shampoos containing different combinations of these surfactants, were tested in order to evaluate their possible toxic effects on microalgae. Specific objective of this research was to compare the sensitivity of selected freshwater and marine microalgae to these widely used surfactants and well-known pollutants in surface waters. Internationally validated methods (ISO standards) for the determination of toxic effects on the growth of planktonic freshwater green algae Pseudokirchneriella subcapitata and Scenedesmus subspicatus and marine diatoms Skeletonema costatum and Phaeodactylum tricornutum, were used. The obtained results showed that the concentrations of tested surfactants and shampoos, which resulted in 50% growth reduction of planktonic freshwater green algae, when compared to the controls without test substances (EC50), were in the range from 0.32 to 4.4 mg l(-1) for surfactants and from 2.1 to 8.5 mg l(-1) for shampoos expressed as active substance. Marine diatoms were significantly more sensitive to the tested surfactants than freshwater green algae (EC50 0.14-1.7 mg l(-1) for surfactants and 0.35-1.25 mg l(-1) for shampoos). According to the classification on the basis of environmental effects, the obtained results suggested that all tested surfactants can be classified as having toxic effects on freshwater green alga Pseudokirchneriella subcapitata. Some of them indicated that they have a very toxic effect on Scenedesmus subspicatus and marine diatoms Skeletonema costatum and Phaeodactylum tricornutum.     

Toxicity of 58 substituted anilines and phenols to algae Pseudokirchneriella subcapitata and bacteria Vibrio fischeri: comparison with published data and QSARs

A congeneric set of 58 substituted anilines and phenols was tested using the 72-h algal growth inhibition assay with Pseudokirchneriella subcapitata and 15-min Vibrio fischeri luminescence inhibition assay. The set contained molecules substituted with one, two or three groups chosen from -chloro, -methyl or -ethyl. For 48 compounds there was no REACH-compatible algal toxicity data available before. The experimentally obtained EC50 values (mg L⁻¹) for algae ranged from 1.43 (3,4,5-trichloroaniline) to 197 (phenol) and for V. fischeri from 0.37 (2,3,5-trichlorophenol) to 491 (aniline). Only five of the tested 58 chemicals showed inhibitory effect to algae at concentrations >100 mg L⁻¹, i.e. could be classified as “not harmful”, 32 chemicals as “harmful” (10-100 mg L⁻¹) and 21 as “toxic” (1-10 mg L⁻¹). The occupied para-position tended to increase toxicity whereas most of the ortho-substituted congeners were the least toxic. As a rule, the higher the number of substituents the higher the hydrophobicity and toxicity. However, in case of both assays, the compounds of similar hydrophobicity showed up to 30-fold different toxicities. There were also assay/organism dependent tendencies: phenols were more toxic than anilines in the V. fischeri assay but not in the algal test. The comparison of the experimental toxicity data to the data available from the literature as well as to QSAR predictions showed that toxicity of phenols to algae can be modeled based on hydrophobicity, whereas the toxicity of anilines to algae as well as toxicity of both anilines and phenols to V. fischeri depended on other characteristics in addition to logK_ow.     

Zinc acclimation and its effect on the zinc tolerance of Raphidocelis subcapitata and Chlorella vulgaris in laboratory experiments.

The effect of zinc acclimation of Raphidocelis subcapitata (syn. Selenastrum capricornutum) and Chlorella vulgaris on their sensitivity towards this metal was examined in a series of laboratory experiments. These two commonly used algal species were acclimated to 65 microg Zn/l and changes in zinc tolerance were monitored using standard growth inhibition tests. The chemically defined ISO medium was used as a control culture medium. Both species demonstrated a maximum increase in zinc tolerance of a factor of 3 after 100 days of acclimation. Shifts in the shape of the concentration-response curve due to acclimation were observed for R. subcapitata. Compared to non-acclimated algae, acclimated R. subcapitata exhibited higher growth rates in all zinc treatments as well as in the controls. This suggests that the use of ISO-medium results in sub-optimal growth due to zinc deficiency. These effects could not be demonstrated for C. vulgaris. The zinc tolerance of both species decreased significantly one week after returning the acclimated algae to control (ISO) medium. 72hEC50 values based on growth rate were two to four times higher than those calculated using biomass measurements. Algal toxicity test results, particularly if used for metal risk assessments, must not be conducted using nutrient deficient media.     

In vitro effect of dimethoate on the activity of tryptophan pyrrolase in rat liver

Total and holo-enzyme activities of tryptophan 2,3-dioxygenase were measured in vitro in the presence and absence of the organophosphorous insecticide, dimethoate. Addition of dimethoate to the reaction mixture decreased the activities of both total and holo-forms. Total and holo-enzyme activities were decreased by 34% and 26%, respectively, by 1 mM dimethoate. On the other hand, 5 mM dimethoate resulted in 56% and 34% inhibition to total and holo-enzyme activities, respectively. Lineweaver-Burk plot of the total-enzyme activity at different tryptophan concentration in the presence of 2 mM dimethoate gave uncompetitive type of inhibition.     

In vitro cytogenetic assessment of trichloroacetic acid in human peripheral blood lymphocytes

Trichloroacetic acid (TCA), a common water disinfection byproduct and a persistent metabolite of trichloroethylene (TCE), has been examined for its genotoxic potential in human lymphocytes. Chromosomal aberration (CA) and cytokinesis-block micronucleus (CBMN) assay were employed to assess the toxicity of TCA. Lymphocytes obtained from three healthy donors were exposed to 25, 50, and 100 μg/ml concentration of TCA separately. TCA exposure resulted in chromosomal anomalies and the formation of micronuclei in lymphocytes. Chromosome analysis revealed the dose-dependent and significant induction of CA. Chromatid break/chromosome break, fragments, and chromatid exchanges were commonly observed. Exposure of higher concentration (50 and 100 μg/ml) significantly inhibited mitotic index. Data obtained with CBMN assay indicated that the induction of micronucleus (MN) formation was greater than that of CA. At 25 μg/ml, TCA induced significant frequencies of MN as compared to control cells. Significant induction of MN at the lowest concentration indicates TCA may also interact with mitotic spindles. Lower percentage of CA and MN at 100 μg/ml as compared to 50 μg/ml indicates occurrence of severe cytotoxicity on exposure of 100 μg/ml TCA in lymphocytes. Collectively, results of both cytogenetic assays indicate that exposure of TCA can induce significant genotoxic and cytotoxic effects.     

Measuring the effect of photocatalytic purifiers on indoor air hydrocarbons and carbonyl pollutants

Laboratory tests of photocatalytic air purifiers are usually performed with a single pollutant, in the parts per million by volume domain and at airflow rates < or =0.1 m3/hr. Clearly, it is necessary to probe photocatalytic materials and apparatuses under real conditions or conditions closely mimicking reality. Photocatalytic prototypes were placed in an ordinary room. To collect hydrocarbons over a shorter period (15 min) than with adsorbent-containing cartridges, solid-phase microextraction (SPME) was used. Typically, concentrations in substituted benzene hydrocarbons and tetrachloroethene were decreased to 20-35% of initial values; toluene and m- + p-xylene concentrations dropped to 2-6 parts per billion by volume, and o-xylene and benzene concentrations were still lower. In the absence of appropriate, commercialized SPME fibers, carbonyl compounds (both formed and destroyed by photocatalysis) were extracted using cartridges containing 2,4- dinitrophenylhydrazine-coated silica. The concentration ranges (in parts per billion by volume) were shifted to higher values in treated air: from 9-15.5 to 12.5-18 for methanal, from 1.5-3 to 8-11.5 for ethanal, and from 4.5-19 to 8-26.5 for propanone with the prototype used; these unprecedented results do not exclude using photocatalysis to treat air, but they illustrate that improvement is needed. Because these tests are time-consuming, preliminary tests are useful; results obtained with a 225-L closed-loop, airtight, photocatalytic reactor with an external turbine enabling the ambient air inside the reactor to be circulated through the purifier device at 15-450 m3/hr flow rates are reported.     

The toxicity of four native Indian plants: effect on AChE and acid/alkaline phosphatase level in fish Channa marulius

The latex of four plants viz. Euphorbia royleana, Jatropha gossypifolia (Euphorbiaceae), Nerium indicum and Thevetia peruviana (Apocynaceae) caused significant reduction in acid/alkaline phosphatase activity and anti-acetylcholinesterase activity in nervous tissue of freshwater air breathing fish Channa marulius. The reduction in the activity of both phosphatases and AChE were time as well as dose dependent.     

In vitro effect of profenofos,fenvalerate and dimilin on protein and RNA biosynthesis by rabbit liver and muscle tissues

Abstract

The present study was carried out to investigate the effect of Curacron (profenofos), Sumicidin (fenvalerate) and Dimilin (di‐fluobenzuron) on the in vitro rate of protein and RNA synthesis by rabbit liver and muscle tissues. The synthesis of protein and RNA were significantly stimulated in the liver and inhibited in the muscle by graded doses of these insecticides. Profenofos showed maximum effect on protein synthesis in both tissues at a dose of 0.2 μg/mL, while the maximum effect on RNA synthesis occurred at 0.2 μg/mL in the liver and at 2 μg/mL in the muscle. Fenvalerate caused maximum stimulation in both liver protein and RNA synthesis at a dose of 2 μg/mL, and maximum inhibition in the muscle at 10 and 0.2 μg/mL for protein and RNA synthesis respectively. The maximum effect of Dimilin on both tissues was reached at 5 μg/mL for protein synthesis and at 0.2 μg/mL for RNA synthesis. The effect of Dimilin on RNA synthesis was more pronounced in both tissues than its effect on protein synthesis, but this trend was reversed in the case of profenofos and fenvalerate. Present data also showed antagonism between these insecticides on the rate of protein and RNA synthesis.     

In vitro effect of profenofos, fenvalerate and dimilin on protein and RNA biosynthesis by rabbit liver and muscle tissues

The present study was carried out to investigate the effect of Curacron (profenofos), Sumicidin (fenvalerate) and Dimilin (difluobenzuron) on the in vitro rate of protein and RNA synthesis by rabbit liver and muscle tissues. The synthesis of protein and RNA were significantly stimulated in the liver and inhibited in the muscle by graded doses of these insecticides. Profenofos showed maximum effect on protein synthesis in both tissues at a dose of 0.2 microgram/mL, while the maximum effect on RNA synthesis occurred at 0.2 microgram/mL, while the maximum effect on RNA synthesis occurred at 0.2 microgram mL in the liver and at 2 micrograms/mL in the muscle. Fenvalerate caused maximum stimulation in both liver protein and RNA synthesis at a dose of 2 micrograms/mL, and maximum inhibition in the muscle at 10 and 0.2 micrograms/mL for protein and RNA synthesis respectively. The maximum effect of Dimilin on both tissues was reached at 5 micrograms/mL for protein synthesis and at 0.2 microgram/mL for RNA synthesis. The effect of Dimilin on RNA synthesis was more pronounced in both tissues than its effect on protein synthesis, but this trend was reversed in the case of profenofos and fenvalerate. Present data also showed antagonism between these insecticides on the rate of protein and RNA synthesis.     

In vitro toxicity of fungicides with different modes of action to alfalfa anthracnose fungus,Colletotrichum destructivum

Abstract

Sensitivity of 24 isolates of Colletotrichum destructivum O’Gara, collected from alfalfa plants in Serbia, to eight selected fungicides, was investigated in this study. Molecular identification and pathogenicity test of isolates tested were also performed. Fungicide sensitivity was evaluated in vitro, using mycelial growth assay method. All isolates exhibited significant pathogenicity, causing necrosis at the alfalfa seedling root tips two days after inoculation. Using the primer pair GSF1-SR1 and by comparing the amplified fragments of the tested isolates with the marker (M), the presence of the amplicon of the expected size of about 900?bp was determined for all isolates. The isolates tested in this study showed different sensitivity towards fungicides in vitro. Mycelial growth was highly inhibited by QoI (quinone outside inhibitors) fungicide pyraclostrobin (mean EC₅₀=0.39?µg mL^?1) and by DMI (demethylation-inhibiting) fungicide tebuconazole (mean EC₅₀=0.61?µg mL^?1), followed by azoxystrobin (mean EC₅₀=2.83?µg mL^?1) and flutriafol (mean EC₅₀=2.11?µg mL^?1). Multi-site fungicide chlorothalonil and MBC (methyl benzimidazole carbamate) fungicide thiophanate-methyl evinced moderate inhibition with mean EC₅₀=35.31 and 62.83?µg mL^?1, respectively. Thirteen isolates were sensitive to SDHI (succinate dehydrogenase inhibitors) fungicide boscalid and fluxapyroxad, (mean EC₅₀=0.49 and 0.19?µg mL^?1, respectively), while the rest of isolates were highly resistant.     

In vitro study of oxytetracycline adsorption on activated charcoal

In vitro adsorption experiments simulating pH in gastric environment and using Langmuir isotherm, showed that 408 mg of oxytetracycline was adsorbed per gram of activated charcoal. Langmuir isotherm fitted adsorption data better than a Freundlich isotherm. Freundlich isotherm showed a specific adsorption capacity of 518 mg/g for activated charcoal. Both isotherm parameters indicated a strong oxytetracycline adsorption on activated charcoal in terms of quantity and binding strength. The results demonstrate that the concomitant use of oxytetracyline and activated charcoal should be avoided.     

In vitro evaluation of the mutagenic and cytostatic effect of Tamaron,Lannate and Manzate alone and in mixture

Pesticides are often used in agriculture, especially in floriculture. They are frequently applied in binary or ternary mixtures. Nevertheless, their impact on the genetic material has been scarcely explored. In this study, the mutagenic and cytostatic effect of three widely used pesticides, alone and combined, were analyzed. Briefly, lymphocytes cultures were obtained from peripheral blood samples of five healthy donors to determine the sister chromatid exchange and the replicative index (RI). Then, lymphocytes were exposed to Tamaron (100 ppm), Lannate (200 ppm) and Manzate (300 ppm) alone and combined. For the binary mixtures, the concentrations used were 50 ppm of Tamaron, 100 ppm of Lannate and 150 ppm of Manzate. For the ternary mixtures the following concentrations were used: Tamaron (33 ppm), Lannate (70 ppm) and Manzate (100 ppm). Finally, differential staining was performed. It was found that the frequency of SCE/cell showed a significant difference (P ≤ 0.05) between the control (2.66) and the individual treatments of Tamaron (4.87), Lannate: (5.12) and Manzate (4.23). Also, the values of the SCE in the binary mixture of Tamaron+Lannate (5.57), Tamaron+Manzate (6.06) and Lannate+Manzate (6.22) and the ternary mixture (6.63) were statistically different compared to the control. In the RI there was a significant difference between the control (1.98) and the Manzate (1.87). RI differences were also statistically significant (P ≤ 0.05) in mixtures of Tamaron+Lannate (1.64), Tamaron+Manzate (1.63), Lannate+Manzate (1.69) and total mixture (1.53). Therefore, it is suggested that these pesticides alone and in mixtures have both mutagenic and cytostatic synergistic effect in human lymphocytes in vitro.     

The joint action of sulphur dioxide and hydrogen fluoride on the yield and quality of wheat and barley

The effects of joint action of SO(2) and HF on the yield and quality of wheat and barley were studied by exposing them to combinations of <13,130 or 267 microg m(-3) SO(2) and 0.03 or 0.38 microg m(-3) HF in open top chambers for 90 days. At the concentrations used, SO(2) had greater effects than HF. All responses were marked by compensatory changes. The treatments had no effect on wheat yield, although SO(2) reduced shoot weight. SO(2) increased the growth and yield of barley, and HF or SO(2) increased the grain protein concentration of barley and wheat. The effects of mixtures of SO(2) and HF were complex, but often antagonistic, as the addition of HF counteracted the effect of SO(2) alone.     

不同草皮构建的湖泊缓冲带对污染物的净化效果研究

选择宜兴地区常见的3种草皮百慕大(Cynodon dactylon)、白花三叶草(Trifolium repens)、高羊茅(Festuca arundinacea),利用自行设计的实验装置模拟构建草皮缓冲带,并模拟宜兴地区降雨时产生的汇流过程和雨量进行太湖缓冲带对陆域面源污染物的净化效果研究.结果表明,草皮缓冲带能有效地截留径流中的SS,3种草皮缓冲带的径流对SS的去除率为百慕大缓冲带＞三叶草缓冲带＞高羊茅缓冲带＞空白对照(不种植草皮的空白土壤),且沿程去除效果增强;草皮缓冲带的渗流对TN、NH3-N、TP净化效果均显著(p＜0.05)高于径流;3种草皮缓冲带在试验槽前0.9m处的污染物去除效果最为明显,湖泊缓冲带的宽度与其污染物截留效果呈正比;总体来说,草皮生物量与其构建的湖泊缓冲带的污染物去除率呈正相关,三叶草和百慕大有较大的地上生物量,其构建的缓冲带表现出较高的污染物去除率,而高羊茅的地上生物量相对较小,其构建的缓冲带污染物去除率也相对较低.     

In vivo chronic effect of dimethoate and deltamethrin on rabbits

The in vivo effect of dimethoate and deltamethrin on body and organ weights, serum proteins and on plasma acetylcholinesterase (AChE), aromatic esterase and ATPase were examined in growing male rabbits throughout five months period. Both compounds had no significant effect on body weight; however, adrenal, testis & pituitary weights decreased (P less than 0.01); the liver and spleen weights increased (P less than 0.01) in a dose dependent manner. Serum total proteins and globulin decreased (P less than 0.01) in a dose dependent trend, while serum albumin was not greatly affected. AChE activity was increased (P less than 0.01) after 1 month of treatment with the two doses of dimethoate and deltamethrin; thereafter, AChE activity showed 40% inhibition of the control level. The activity of aromatic esterase increased markedly after the first month, then declined gradually until the fifth month. High dose of dimethoate markedly inhibited this enzyme particularly after the 5th month of treatment. Both doses of deltamethrin increased ATPase activity after the first month of treatment, then the ATPase activity was normal. Dimethoate inhibited ATPase particularly at the end of treatment in a dose dependent manner.     

Decolorization and decomposition of organic pollutants for reactive and disperse dyes using electron beam technology: effect of the concentrations of pollutants and irradiation dose

Dyeing wastewater was known to have strong color and refractory organic pollutants. In this study irradiation alone was used for dyes wastewater treatment. This paper studies the effect of the concentrations of pollutants to its removal at various dosages using electron beam technology. Irradiation was effective in removing the highly colored and refractory organic compounds. The color removal for initial concentrations of 255 CU, 520 CU, 990 CU and 1900 CU treated using irradiation at 0.5kGy were 61%, 48%, 28% and 16%, respectively. However, at the dose of 108kGy and higher, the color removal between 87% and 96% were recorded with no apparent trend. COD removal also reported similar trend but at relatively lower removal percentage. The COD removal at 0.5kGy for initial COD concentrations of 57mg/l and 515mg/l were 10% and 0%, respectively. At irradiation dose of 108kGy, the removal for initial COD concentrations of 57mg/l and 515mg/l were 37% and 13%, respectively. This showed that concentrations of pollutants and dose of irradiation applied to remove color and COD were dependent to each other.