Is the Cry1Ab Protein from Bacillusthuringiensis (Bt) Taken Up by Plants from Soils Previously Planted with Bt Corn and by Carrot from Hydroponic Culture?

The uptake of the insecticidal Cry1Ab protein from Bacillus thuringiensis (Bt) by various crops from soils on which Bt corn had previously grown was determined. In 2005, the Cry1Ab protein was detected by Western blot in tissues (leaves plus stems) of basil, carrot, kale, lettuce, okra, parsnip, radish, snap bean, and soybean but not in tissues of beet and spinach and was estimated by enzyme-linked immunosorbent assay (ELISA) to be 0.05 ± 0.003 ng g⁻¹ of fresh plant tissue in basil, 0.02 ± 0.014 ng g⁻¹ in okra, and 0.34 ± 0.176 ng g⁻¹ in snap bean. However, the protein was not detected by ELISA in carrot, kale, lettuce, parsnip, radish, and soybean or in the soils by Western blot. In 2006, the Cry1Ab protein was detected by Western blot in tissues of basil, carrot, kale, radish, snap bean, and soybean from soils on which Bt corn had been grown the previous year and was estimated by ELISA to be 0.02 ± 0.014 ng g⁻¹ of fresh plant tissue in basil, 0.19 ± 0.060 ng g⁻¹ in carrot, 0.05 ± 0.018 ng g⁻¹ in kale, 0.04 ± 0.022 ng g⁻¹ in radish, 0.53 ± 0.170 ng g⁻¹ in snap bean, and 0.15 ± 0.071 ng g⁻¹ in soybean. The Cry1Ab protein was also detected by Western blot in tissues of basil, carrot, kale, radish, and snap bean but not of soybean grown in soil on which Bt corn had not been grown since 2002; the concentration was estimated by ELISA to be 0.03 ± 0.021 ng g⁻¹ in basil, 0.02 ± 0.008 ng g⁻¹ in carrot, 0.04 ± 0.017 ng g⁻¹ in kale, 0.02 ± 0.012 ng g⁻¹ in radish, 0.05 ± 0.004 ng g⁻¹ in snap bean, and 0.09 ± 0.015 ng g⁻¹ in soybean. The protein was detected by Western blot in 2006 in most soils on which Bt corn had or had not been grown since 2002. The Cry1Ab protein was detected by Western blot in leaves plus stems and in roots of carrot after 56 days of growth in sterile hydroponic culture to which purified Cry1Ab protein had been added and was estimated by ELISA to be 0.08 ± 0.021 and 0.60 ± 0.148 ng g⁻¹ of fresh leaves plus stems and roots, respectively. No Cry1Ab protein was detected in the tissues of carrot grown in hydroponic culture to which no Cry1Ab protein had been added. Because of the different results obtained with different commercial Western blot (i.e., from Envirologix and Agdia) and ELISA kits (i.e., from Envirologix, Agdia, and Abraxis), it is not clear whether the presence of the Cry1Ab protein in the tissues of some plants under field condition and in carrot in sterile hydroponic culture was the result of the uptake of the protein by the plants or of the accuracy and sensitivity of the different commercial kits used. More detailed studies with additional techniques are obviously needed to confirm the uptake of Cry proteins from soil by plants subsequently planted after a Bt crop.     

Evaluation onto life cycle parameters of Ceriodaphnia silvestrii submitted to 36 days dietary copper exposure

The present study aimed to investigate the response of several life history parameters (body length and age of primipara, duration of embryonic development, maximum body length, reproduction and survival) of the zooplankton Ceriodaphnia silvestrii while exposed to copper contaminated algae Pseudokirchneriella subcapitata. In order to evaluate chronic exposure on the animal's life history, long-term experimental design was used. Cladocerans were fed with a dietary copper concentration ranging from 3 to 68 fg Cu cell⁻¹. Low waterborne copper exposure (around 10⁻¹⁰ mol L⁻¹ free Cu²⁺ ions) was kept in the experiments. The results showed that by exposure of cladocerans during 7 days to contaminated food with 68 fg Cu cell⁻¹, a significant reduction in neonate production, survival and body size were obtained. Inhibition on egg production of zooplankton at 38 fg Cu cell⁻¹ were observed in 36 days chronic dietary copper exposure. The importance of entire life cycle study to better evaluate cladoceran responses to chronic dietary metal exposure was demonstrated.     

Effectiveness of glyphosate and imazamox on the control of the invasive cordgrass Spartina densiflora

The south-American cordgrass, Spartina densiflora, has become the dominant plant species on recent tidal marsh restorations in the Doñana National Park (SW Spain). We examined the effect of different doses of glyphosate (720–7200 g a.i. ha⁻¹) and imazamox (20–68 g a.i. ha⁻¹) on growth and photosynthetic apparatus of S. densiflora. Imazamox had no effect on neither on growth nor photosynthetic apparatus of S. densiflora. On the contrary, glyphosate inhibited photochemical efficiency of photosynthesis from day one. Net photosynthetic rate, stomatal conductance and photosynthetic pigments and the number of new tillers were reduced. Glyphosate at high doses (ca. 7200 g a.i. ha⁻¹) could be an appropriate method of control, since it has a negative effect over the photosynthetic apparatus and growth of S. densiflora. Furthermore, glyphosate and its main metabolite, AMPA, were not extracted from the soil, since they were retained by the very high iron and aluminum oxide content of this soil.     

Benzo(a)pyrene shows low toxicity to three species of terrestrial plants, two soil invertebrates, and soil-nitrifying bacteria

We examined the toxicity of benzo(a)pyrene (BaP) to several standard test organisms including the seed emergence and early life-stage growth of three terrestrial plants (Trifolium pratense, Lolium perenne, and Brassica alba), the survival and reproduction of enchytraeids (Enchytraeus crypticus), and the nitrifying ability of soil bacteria. To also have a look at possible food-chain effects, we included a two-species reproduction test with predatory mites (Hypoaspis aculeifer) and collembolan (Folsomia fimetaria) prey. No effect or only weak effects even at very high BaP concentrations were observed for all tests. None of the soil invertebrates were affected within the concentration range tested (up to 947 mg kg⁻¹). For soil-nitrifying bacteria, significant effects were recorded at 977 mg kg⁻¹, leaving a no observable effect concentration (NOEC) of 293 mg kg⁻¹. BaP did not affect seed emergence for any of the plants, but the growth of B. alba was significantly reduced at the highest concentration tested (375 mg kg⁻¹), leaving a NOEC of 69 mg kg⁻¹. Compared to a number of other polycyclic aromatic compounds previously tested in the same soil type, BaP is generally less toxic.     

Analysis of trans-resveratrol: Comparison of methods and contents in Muscatel fortified wines from Setúbal region in Portugal

Liquid chromatography and mass spectrometry conditions were developed in order to identify trans-resveratrol in sweet fortified Muscatel wines from Setúbal region (Portugal). Diode array, fluorescence and electrochemical detectors were used for quantitation purposes. The detection and quantitation limits for each detection mode were: 0.02 and 0.06 mg L⁻¹ for UV–vis, 0.01 and 0.03 mg L⁻¹ for fluorescence and 0.45 and 1.35 mg L⁻¹ for electrochemical. Repeatibility (n=6) expressed as the relative standard deviation of peak areas for a standard solution of trans-resveratrol (1.75 mg L⁻¹) was 0.5% for fluorescence and 1.5% for UV–vis and electrochemical detection modes. Samples collected at one representative producer, during the winemaking process, were injected without pre-treatment and the quantitation of trans-resveratrol was carried out using fluorimetric detection. The trans-resveratrol content decreased slightly along the winemaking process and the concentrations ranged from 0.22±0.02 to 0.16±0.02 mg L⁻¹.After maturation stages, trans-resveratrol contents in wines collected at different producers were compared: values obtained range from 0.13±0.02 to 0.38±0.03 mg L⁻¹. The trans-resveratrol contents in commercially available wines from the same producers were lower.     

Bioaccumulation and toxicity of sediment associated herbicides (ioxynil, pendimethalin, and bentazone) in Lumbriculus variegatus (Oligochaeta) and Chironomus riparius (Insecta)

The benthic macroinvertebrates Lumbriculus variegatus and Chironomus riparius were used in toxicity and bioaccumulation tests to determine the toxic concentrations and accumulation potential of sediment associated herbicides. The tested chemicals were ioxynil, bentazone, and pendimethalin. The bioaccumulation tests with L. variegatus were performed in four different sediments, each having different characteristics. Water-only LC₅₀ tests were performed with both L. variegatus and C. riparius. A sublethal effect of model compounds in sediments was assessed by a C. riparius larvae growth-inhibition test. Of the model compounds, ioxynil appeared to be the most toxic, with LC₅₀ values 1.79 and 2.79 mg L⁻¹ for L. variegatus and C. riparius, respectively. The LC₅₀ water concentrations for bentazone were 79.11 and 62.31 mg L⁻¹ for L. variegatus and C. riparius, respectively. Similarly, ioxynil revealed the highest bioaccumulation potential in bioaccumulation tests. The most important characters affecting chemical fate in the sediment seemed to be the organic matter content and the particle size fraction. The sediments with low organic material and coarse particle size consistently showed high bioaccumulation potential and vice versa. In C. riparius growth tests bentazone had a statistically significant effect on larval growth at sediment concentrations of 1160 and 4650 mg kg⁻¹ (P<0.05). It is noteworthy that standard deviations tend to be greater at high chemical concentrations, which addresses the fact that part of the individuals started to suffer. Ioxynil had an effect on the larval growth in other test sediment at the highest concentration (15.46 mg kg⁻¹ dw), in which head capsule length correlated with larval weight, decreasing toward higher exposure concentrations. The current results show the importance of sediment organic matter as a binding site of xenobiotics.     

Does Cry1Ab protein affect learning performances of the honey bee Apis mellifera L. (Hymenoptera, Apidae)?

Genetically modified Bt crops are increasingly used worldwide but side effects and especially sublethal effects on beneficial insects remain poorly studied. Honey bees are beneficial insects for natural and cultivated ecosystems through pollination. The goal of the present study was to assess potential effects of two concentrations of Cry1Ab protein (3 and 5000 ppb) on young adult honey bees. Following a complementary bioassay, our experiments evaluated effects of the Cry1Ab on three major life traits of young adult honey bees: (a) survival of honey bees during sub-chronic exposure to Cry1Ab, (b) feeding behaviour, and (c) learning performance at the time that honey bees become foragers. The latter effect was tested using the proboscis extension reflex (PER) procedure. The same effects were also tested using a chemical pesticide, imidacloprid, as positive reference. The tested concentrations of Cry1Ab protein did not cause lethal effects on honey bees. However, honey bee feeding behaviour was affected when exposed to the highest concentration of Cry1Ab protein, with honey bees taking longer to imbibe the contaminated syrup. Moreover, honey bees exposed to 5000 ppb of Cry1Ab had disturbed learning performances. Honey bees continued to respond to a conditioned odour even in the absence of a food reward. Our results show that transgenic crops expressing Cry1Ab protein at 5000 ppb may affect food consumption or learning processes and thereby may impact honey bee foraging efficiency. The implications of these results are discussed in terms of risks of transgenic Bt crops for honey bees.     

The Effects of Bt Corn on Rusty Crayfish (Orconectes Rusticus) Growth and Survival

Bt crops are one of the most commonly used genetically modified crops worldwide. Bt crops contain a gene that is derived from the bacteria Bacillus thuringiensis, which produces the Cry1Ab toxin. Bt corn that contains the Cry1Ab toxin is used throughout the Midwest United States to control crop pests such as the European corn borer (Ostrinia nubilalis). Headwater streams in regions known for intensive agriculture receive Bt corn detritus after the fall harvest, which is then consumed by a diverse community of stream invertebrates. The rusty crayfish (Orconectes rusticus) is a common invertebrate detritivore in these headwater streams. Both isogenic and Bt corn were grown under the controlled environmental conditions of a greenhouse and, after senescence, were tested for nutritional equality. Rusty crayfish were exposed to one of several detrital treatments composed of Bt corn, Bt corn plus American sycamore (Platanus occidentalis), isogenic corn alone, isogenic corn plus P. occidentalis, or P. occidentalis alone for 8 weeks. Both strains of corn were grown under the controlled environmental conditions in a greenhouse and were tested for nutritional equality after senescence. Crayfish were housed in live streams with a water temperature of 12.8 °C and a 12:12 h light-to-dark photoperiod. Survival and growth of animals within each experimental treatment were monitored each week. After 8 weeks of exposure, there was no statistically significant difference in growth between crayfish in Bt and isogenic treatments. However, survivorship was 31 % lower in the Bt treatment compared with the isogenic treatment. These results suggest that the Bt corn and isogenic corn were of equivalent nutritional value but that Bt corn does have a toxic effect on rusty crayfish during long-term exposure.     

Total and individual carotenoid profiles in Solanum phureja of cultivated potatoes: I. Concentrations and relationships as determined by spectrophotometry and HPLC

Total and individual carotenoid concentrations were determined by spectrophotometry and HPLC, in raw tubers of a sample of 23 accessions of Solanum phureja potatoes taken at random from the world germplasm collection following its stratification on tuber flesh color. Lutein, zeaxanthin, violaxanthin, antheraxanthin and β-carotene were detected in all accessions and three distinct patterns of carotenoid accumulation were evidenced by cluster analysis. Accessions in group 1 showed the highest concentrations of total carotenoids (1258–1840 μg 100 g⁻¹ FW) comprised largely of zeaxanthin (658–1290 μg 100 g⁻¹ FW) with very low or no presence of β-carotene (below 5.4 μg 100 g⁻¹ FW). Accessions in group 2 presented moderate total carotenoid concentrations with violaxanthin, antheraxanthin, lutein and zeaxanthin as the major carotenoids. Accessions in group 3 showed low concentrations of total carotenoids (97–262 μg 100 g⁻¹ FW) and very low or no zeaxanthin, with lutein and violaxanthin as the predominant carotenoids and relatively high concentrations of β-carotene (up to 27 μg 100 g⁻¹ FW). Five accessions with significant concentrations of zeaxanthin were identified with the accession 703566 showing the highest concentration (1290 μg 100 g⁻¹ FW). This value is to our knowledge higher than any value previously reported for potatoes, including those achieved through genetic modification. For the 23 S. phureja accessions, total carotenoid concentration was positively and significantly correlated with antheraxanthin and zeaxanthin concentrations, and negatively and significantly correlated with β-carotene concentration.     

Toxicity and removal of heavy metals (cadmium, copper, and zinc) by Lemna gibba

Effects of cadmium, copper, and zinc on the aquatic plant Lemna gibba were determined under controlled conditions; in parallel their removal from the growth medium was followed. The results showed that the three heavy metals affected growth, a physiological stress index defined as the ratio of Chlorophyll to phaeophytin (D665/D665a), and the contents of proline. After 4 days, 10⁻³–10⁻¹ mg/L Cd inhibited growth by 25–100%, reduced D665/D665a by 35–89%, and increased proline content by 44–567%. Under the same conditions, 10⁻⁴–10⁻¹ μg/L Cu inhibited growth by 36–75%, reduced D665/D665a by 19–81%, and increased proline content by 67–288%. Comparable concentrations of Zn had little effect. However, higher concentrations (4, 30, and 50 mg/L) inhibited growth by 50–79%. Also, 0.1 and 30 mg/L induced a small reduction of D665/D665a (−3.8% and −22%) and an increase in proline contents (+144% and +177%). When it was observed, proline accumulation was always transient and the maximum was reached after 4 days. Monitoring metal concentration in the medium showed that L. gibba was able to remove metals from the medium. Zn and Cu removal was biphasic, it was rapid during the first 2 days (> 60% reduction) and slow (10–20%) during the following 8 days. For Cd, removal was linear and depended on the initial concentration. It reached approximately 90% after 6 or 8 days for initial concentrations of 10⁻¹ and 10⁻³ mg/L, respectively.     

Determination of Myo-inositol and d-chiro-inositol in black rice bran by capillary electrophoresis with electrochemical detection

A high-performance capillary electrophoresis (CE) method with electrochemical detection (ED) is developed for simultaneous determination of myo-inositol and d-chiro-inositol in black rice bran in this work. A 140 μm diameter copper-disk electrode operated in a wall-jet configuration, which exhibited good response at +0.65 V (relative to the saturated calomel electrode (SCE)) for the two analytes in 50 mm sodium hydroxide solution, was used as working electrode. The optimum conditions for determination was optimized with regard to the potential applied to the working electrode, concentration of the running buffer, separation voltage and injection time. The analytes were separated within 20 min. Excellent linearity was obtained in the concentration range from 1.0×10⁻⁶ to 1.0×10⁻⁴ g/ml for both analytes. The detection limit (S/N=3) was 5.3×10⁻⁷ and 7.3×10⁻⁷ g/ml for myo-inositol and d-chiro-inositol, respectively. The work provides a useful method for the analysis of myo-inositol and d-chiro-inositol in black rice bran.     

Toxic Effects of Cadmium on Reproduction, Development, and Hatching in the Freshwater SnailLymnaea stagnalisfor Water Quality Monitoring

The freshwater snailLymnaea stagnaliswas exposed to cadmium concentrations of 0, 25, 50, 100, 200, and 400 μg liter⁻¹. The influence of this highly toxic metal on various stages of reproduction (number of egg masses, number of eggs, embryo development, and hatching) was studied. Egg production ceased at 400 μg Cd²⁺liter⁻¹and hatching was reduced to 0.4% with 200 μg liter⁻¹at 20°C. The study revealed that embryo development was the most sensitive stage, the main anomalies observed depending on the Cd²⁺concentration. At the highest concentration studied (400 μg liter⁻¹) the eggs were blocked in the first cleavage stage. At 100 and 200 μg Cd²⁺liter⁻¹, development of the eggs was halted at various stages of embryogenesis (cleavage, gastrula, veliger, and prehatching) depending on their position in the egg masses. At concentrations of 25 to 100 μg Cd²⁺liter⁻¹, development was slowed down and hatching occurred 5 to 15 days later than in the controls (controls hatched 12 to 13 days after laying). The results obtained demonstrate the effects of Cd²⁺on reproduction and development inL. stagnalisand provide information on the targets affected (neuroendocrine control of laying or cell multiplication and organogenesis of the embryos). It is thus possible to predict the probability of survival of the species in an environment polluted with cadmium and to compare it with the effects of other pollutants in the same or other species.     

Acute and chronic effects of testosterone and 4-hydroxyandrostenedione to the crustacean Daphnia magna

Steroid compounds have been globally detected in surface waters. The ecological impacts of these biologically active chemicals are largely unknown. Toxicity of testosterone and 4-hydroxyandrostenedione was assessed for the freshwater cladoceran Daphnia magna. Acute toxicity tests showed that 6.20 mg L⁻¹ of testosterone, the highest concentration tested, did not have effect on the daphnids, whereas 4-hydroxyandrostenedione had an EC₅₀ of 4.26 mg L⁻¹. Chronic toxicity tests were carried out using survival, body length, fecundity, and fertility as endpoints. Long-term testosterone exposure reduced D. magna fecundity and fertility at concentrations ranging from 0.31 to 2.48 mg L⁻¹. The significant decrease in fecundity was associated with an increase in aborted eggs. Long-term 4-hydroxyandrostenedione exposure at 0.84 mg L⁻¹ increased the mortality of the neonates. The chronic toxicity effects were observed at concentrations higher than the measured environmental concentrations of these compounds. Nevertheless, the reproductive impairment of the daphnids is likely to occur at environmental levels as an ultimate response to long-term exposure.     

Toxicity of four nitrogen-heterocyclic polyaromatic hydrocarbons (NPAHs) to soil organisms

The aims of this study were: (i) to investigate the toxicity of N-heterocyclic polyaromatic hydrocarbons (NPAHs) quinoline, acridine, phenazine, and 1,10-phenanthroline to the soil invertebrates Eisenia fetida, Enchytraeus crypticus, Folsomia candida, and Caenorhabditis elegans, (ii) to compare the toxicity of four NPAHs and the species sensitivity, and (iii) to discuss possible risks of these compounds in soils. Different toxicities were found for the tested NPAHs which might be partially explained by their structure and properties. Effect concentrations expressed as soil pore-water concentrations were related to log K_ow, which indicated narcosis as the most probable mode of toxic action. The species sensitivity decreased in the rank: springtails >enchytraeids=earthworms> nematodes. Predicted no-effect concentration (PNEC) values were calculated for all tested species giving values from 0.5 to 6.8 mg/kg. It is unlikely that there is a risk for soil organisms in natural soils where lower NPAHs concentrations are expected.     

Bioaccumulation of heavy metals in Liza saliens from the Esmoriz-Paramos coastal lagoon, Portugal

Heavy metal (Cu and Zn) concentrations in liver, gills, and muscle of leaping grey mullet, Liza saliens, from the Portuguese Esmoriz–Paramos coastal lagoon were measured to evaluate their bioaccumulation as a function of sediment contamination. The highest metal concentrations were observed in the liver (254 mg Cu kg⁻¹) and gills (114 mg Zn kg⁻¹). Bioaccumulation factors (BAFs) were found to follow the order: Cu-liver>Cu-gills>Cu-muscle and Zn-gills>Zn-liver>Zn-muscle. The highest BAFs were observed in the organs mainly implicated in metal metabolism and a significant positive relationship was found between BAFs and fish age. These results suggest the loss of homeostatic capacity of L. saliens under chronic metal exposure leading to bioaccumulation. Furthermore, Cu-liver and Zn-gills accumulation can be good environmental indicators of metal stress in L. saliens.     

Potential of vetiver (Vetiveria zizanoides L. Nash) for phytoremediation of phenol

Aseptically grown Vetiveria zizanoides were evaluated for their potential for phytoremediation of phenol from Murashige and Skoog's liquid medium. Phenol was found to be completely removed from incubation medium at the end of 4 days by V. zizanoides plantlets, when medium was supplemented with 50 and 100 mg L⁻¹ phenol, while with 200, 500, and 1000 mg L⁻¹ of phenol, 89%, 76% and 70%, respectively, were removed. Phenol removal was found to be associated with inherent production of peroxidase and hydrogen peroxide. Coupled with H₂O₂ formation, the levels of antioxidant enzymes like superoxide dismutase and peroxidase showed an enhancement when plants were exposed to phenol, whereas catalase levels initially showed a decline due to the utilization of H₂O₂ by peroxidase for phenol oxidation. However, when peroxidase levels declined, there was an enhancement in catalase levels to minimize the presence of H₂O₂ in the medium. Having confirmed that the removal of phenol was by V. zizanoides plantlets, in the next phase, micropropagated plantlets and well-developed plants grown in hydroponics were used under in vivo conditions to study the effect of phenol (200 mg L⁻¹) on plant growth and reuse. Although plant growth was reduced in presence of phenol, the results of the reuse study indicated the possibility of plants getting adapted to phenol without any decline in potential for phenol remediation.     

Distribution of Free Seleno-amino Acids in Plant Tissue ofMelilotus indicaL. Grown in Selenium-Laden Soils

Accumulation of specific groups of seleno-amino acids in plant tissue reflects not only the Se tolerance of a plant species, but also Se toxicity to animals. The distribution of seleno-amino acids in a Se-tolerant grassland legume species (Melilotus indicaL.) grown in Se-laden soils was studied using high-resolution gas chromatography-and gas chromatography-mass spectrometry. Five seleno-amino acids including selenocystine, selenomethionine, selenocysteine, Se-methylselenocystine, andγ-glutamyl-Se-methylselenocysteine were identified and measured for their plant tissue concentrations. Se-methylselenocysteine, a nonprotein seleno-amino acid, was found in the plant tissue. Its concentration ranged from 15.3 μmol kg⁻¹for the plants growing in soil of low Se concentration to 109.8 μmol kg⁻¹for the plants grown in soil of high Se concentration. Accumulation of the nonprotein seleno-amino acid in this species resembles that in Se accumulator plants.γ-Glutamyl-Se-methylselenocysteine was detected in the plant. However, its concentration was very low. It might not become a toxic element in the food chain. Results of plant tissue Se accumulation analysis indicated that there was a five-fold increase in tissue selenocysteine concentration when the total tissue Se increased from 5.07 to 22.02 mg kg⁻¹, but there was no further increase in tissue selenocysteine concentration when the tissue total Se concentration increased from 22.0 to 117.4 mg kg⁻¹. Selenomethinone constituted more than 50% of the total seleno-amino acid in the plant. More research is needed to reveal whether the mechanisms limiting the accumulation of selenocysteine and preferential accumulation of selenomethionine found in this study play any role in Se tolerance in this species.     

Embryo-toxic effects of environmental concentrations of chlorpyrifos on the crustacean Daphnia magna

Chlorpyrifos is a non-systemic organophosphorus insecticide leading to the inhibition of the enzyme cholinesterase. Nowadays, this insecticide is widely used on a variety of crops and is frequently detected in surface waters around the world. The main aims of this study were to evaluate the effects of this insecticide on the embryonic development of Daphnia magna, and to assess the sensitivity of this endpoint in comparison with the endpoint of the chronic 21-day test. The featured endpoints were the number of offspring per female and abnormalities of both offspring and embryos. Chlorpyrifos exhibited significant toxic effects on the embryonic development manifested in the appearance of abnormalities, including arrested eggs, in 20% of the embryos exposed to a concentration of 0.01 μg L⁻¹. Furthermore, chronic exposition to the insecticide yielded a proportion of offspring abnormalities in later stages of development of about 43% at 0.01 μg L⁻¹. In contrast, a significant reduction in the number of offspring produced per female was only observed above a concentration of 0.03 μg L⁻¹. Hence, these results suggest that developmental abnormality was a more sensitive endpoint than the number of offspring production per female.     

<Emphasis Type="Italic">Spirulina</Emphasis> enhanced the skeletal muscle protein in growing rats

Background/Aim of the study  This study evaluates the effects of the blue green alga spirulina as the sole dietary source of protein on muscle protein in weaning rats. Methods  Young (30 days) Wistar rats were fed, during 60 days, with 17% protein spirulina (S) and compared to rats fed 17% protein casein (C). We evaluated the muscle total protein and DNA contents and the in vitro protein synthesis and degradation rates as well the myosin protein expression. Results  The groups presented similar body weight (C = 427.3 ± 8.6; S = 434.6 ± 7.7 g) and length (C = 25.4 ± 0.2; S = 25.6 ± 0.2 cm). Soleus muscle total protein (C = 2.9 ± 0.1; S = 2.7 ± 0.1 mg/100 mg) and DNA (C = 0.084 ± 0.005; S = 0.074 ± 0.005 mg/100 mg) contents were also similar in both groups. Protein degradation (C = 427.5 ± 40.6; S = 476.7 ± 50.5 pmol/mg⁻¹ h⁻¹) did not differ between the groups but protein synthesis (C = 17.5 ± 1.0; S = 25.2 ± 1.9 pmol/mg⁻¹ h⁻¹) and myosin content (western blot analyses) were higher (P < 0.05, t test) in spirulina group. Conclusions  Although the spirulina proved adequate protein quality to maintain body growth, the muscle protein synthesis rates were increased by the ingestion of the experimental diet in young rats.