Refine search
Results 1451-1460 of 1,540
Production of monoclonal antibody and application in indirect competitive ELISA for detecting okadaic acid and dinophytoxin-1 in seafood
2012
Lu, Shi-Ying | Zhou, Yu | Li, Yan-Song | Lin, Chao | Meng, Xian-Mei | Yan, Dong-Ming | Li, Zhao-Hui | Yu, Shi-Yu | Liu, Zeng-Shan | Ren, Hong-Lin
BACKGROUND, AIM, AND SCOPE: Okadaic acid (OA) and analogues of dinophysistoxin (DTX) are key diarrheic shellfish poisoning (DSP) toxins, which possibly arouse DSP symptoms by consuming the contaminated shellfish. Because of the stable toxicity in high temperature and the long-term carcinogenicity, the outbreaks of DSP related to consumption of bivalve mollusks contaminated by DSP toxins pose a hazard to public health. Therefore, it is worth developing a fast and reliable analytical method for the detection of OA and analogues in shellfish. In this paper, an indirect competitive enzyme-linked immunosorbent assay (ELISA) (icELISA) for detecting OA and DTX-1 in seafood was developed based on monoclonal antibody (McAb). METHODS: The OA was conjugated to human immunoglobulin G (IgG) and bovine serum albumin (BSA) by the active ester method as the immune antigen and the detective antigen. The spleen cells from BALB/c mice immunized with OA-IgG were fused with SP2/0 myeloma cells. A hybridoma cell line, which secreted McAb against OA, was selected by “limiting dilution” cloning. An icELISA was developed based on immobilized conjugate (OA-BSA) competing the McAb with the free OA in seafood sample. RESULTS: A hybridoma cell line, which secreted IgG1 subclass monoclonal antibody (McAb) against OA, was selected. The IC₅₀ of the McAb for OA and dinophytoxin-1 (DTX-1) were 4.40 and 3.89 ng/mL, respectively. Based on the McAb, an indirect competitive ELISA for detection of OA and DTX-1 in seafood was developed. The regression equation was y = 54.713x − 25.879 with a coefficient correlation of R ² = 0.9729. The linear range and the limit of detection were 0.4–12.5 and 0.45 ng/mL, respectively. The average recovery of OA and DTX-1 spiked shellfish was 82.29% with the coefficient of variation of 7.67%. CONCLUSION: The developed icELISA is a fast, sensitive, and convenient assay for detecting of total amount of OA and DTX-1 in seafood.
Show more [+] Less [-]Plasma esterases in the tegu lizard Tupinambis merianae (Reptilia, Teiidae): impact of developmental stage, sex, and organophosphorus in vitro exposure
2012
Basso, Agustín | Attademo, Andrés M. | Lajmanovich, Rafael C. | Peltzer, Paola M. | Junges, Celina | Cabagna, Mariana C. | Fiorenza, Gabriela S. | Sanchez-Hernandez, Juan Carlos
PURPOSE: In this study, we determined normal serum butyrylcholinesterase (BChE) and carboxylesterase (CbE) activities in Tupinambis merianae in order to obtain reference values for organophosphorus pesticide monitoring. METHODS: Forty-two T. merianae individuals were grouped by sex and size to identify potential differences in their enzyme levels to allow for proper representation of normal values for females, males, juveniles, and hatchlings. Mean CbE was determined using two model substrates: alpha-naphtylacetate (α-NA) and p-nitrophenyl valerate (4-NPV). BChE and CbE sensitivity to malaoxon (Mx) was also evaluated as well as the possibility of BChE reactivation with pyridine-2-aldoxime methochloride (2-PAM). RESULTS: Mean adult females’ BChE was significantly higher than adult males, juveniles, and hatchlings. No significant differences were found between groups regarding CbE. CbE (4-NPV) activity showed slightly negative correlation with lizard snout–vent length, while BChE and CbE (α-NA) showed no correlation with body size. Apparent IC50 values for BChE and CbE (α-NA) suggested different sensitivities among groups. CbE (4-NPV) could not be inhibited. All Mx-inhibited groups treated with 2-PAM in a final concentration of 2.8 mM showed clear signs of reactivation. CONCLUSIONS: In conclusion, the results demonstrate that (1) plasma esterase activity did not vary with age and sex, except for BChE activity, and (2) because biological and environmental variables could be confounding factors in the response of plasma cholinesterases, complementary biomarkers like CbE inhibition and oxime-induced reactivation of esterases are strongly recommended.
Show more [+] Less [-]Toxicity test using medaka (Oryzias latipes) early fry and concentrated sample water as an index of aquatic habitat condition
2012
Yamashita, H. | Haribowo, R. | Sekine, M. | Oda, N. | Kanno, A. | Shimono, Y. | Shitao, W. | Higuchi, T. | Imai, T. | Yamamoto, K.
The aim of the present study was to show a relationship between toxicity of 100-fold concentrated water and aquatic habitat conditions. Environmental waters are 100-fold concentrated with solid-phase extraction. Medaka early fry was exposed in these waters for 48 h. The number of death and disorder was counted at 1, 2, 3, 6, 12, 24, and 48 h; toxicity was expressed using inverse median effect time and median lethal time (ET ₅₀ ⁻¹ , LT ₅₀ ⁻¹ ). Average score per taxon (ASPT) for benthic animals and Index of Biotic Integrity (IBI) for fish were applied as indices of aquatic habitat conditions. The results of toxicity test were compared using ASPT and IBI. The different levels of toxicity were detected in the seawater of Japan. At the Husino River area, toxicity cannot be detected. In rivers, high toxicity appeared at urban districts without sewerage. By Spearman coefficient, the relationship between toxicity and high biochemical oxygen demand (BOD) were obtained. BOD household wastewater contains hydrophobic toxic matters; otherwise, seawater in industrial area does not show clear relationship between toxicity and chemical oxygen demand. Gas chromatography to mass spectrometry simultaneous analysis database may give an answer for the source of toxicity, but further test is required. Ratio of clear stream benthic animal sharply decreased over 0.25 of LT ₅₀ ⁻¹ or 0.5 of ET ₅₀ ⁻¹ . Tolerant fish becomes dominant over 0.3 of LT ₅₀ ⁻¹ or 0.5–1.0 of ET ₅₀ ⁻¹ . By Pearson product–moment correlation coefficient, correlation coefficient between toxicity and ASPT was obtained at −0.773 (ET ₅₀ ⁻¹ ) and −0.742 (LT ₅₀ ⁻¹ ) at 1 % level of significance with a high negative correlation. Toxicity (LT ₅₀ ⁻¹ ) has strong correlation with the ratio of tolerant species. By Pearson product–moment correlation coefficient, correlation coefficient between toxicity and IBI obtained were −0.155 (ET ₅₀ ⁻¹ ) and −0.190 (LT ₅₀ ⁻¹ ) at 1 % level of significance and has a low or no correlation between toxicity and IBI. Even with low toxic environmental waters, toxicity test using 100-fold concentrated and medaka early fly could detect acute toxicity. The detected toxicity seemed to limit the inhabiting aquatic species in the water body.
Show more [+] Less [-]Performance of Eleocharis macrostachya and its importance for arsenic retention in constructed wetlands
2012
Olmos-Márquez, Mario Alberto | Alarcón Herrera, María Teresa | Martín-Domínguez, Ignacio Ramiro
INTRODUCTION: Arsenic (As) can be removed from water via rhizofiltration using phytostabilizing plants. The aim of this study was to investigate the performance of Eleocharis macrostachya in constructed wetland prototypes, as well as the plant's arsenic mass retention and the distribution of As along the wetland flow gradient and the soil in the wetland mesocosmos. MATERIALS AND METHODS: Experiments were carried out in laboratory-scale wetland prototypes, two planted with E. macrostachya and one without plants. Samples of water were taken at the inlet and outlet of the wetlands during the 33-week test period. At the end of the experiment, plants and soil (silty-sand) from each prototype were divided in three equal segments (entrance, middle and exit) and analyzed for their arsenic content. Results revealed that the planted wetlands have a higher As-mass retention capacity (87–90% of the total As inflow) than prototypes without plants (27%). RESULTS: As mass balance in the planted wetlands revealed that 78% of the total inflowing As was retained in the soil bed. Nearly 2% was absorbed in the plant roots, 11% was flushed as outflow, and the fate of the remaining 9% is unknown. In the prototype without plants, the soil retained 16% of As mass, 72% of the arsenic was accounted for in the outflow, and 12% was considered unknown. Although E. macrostachya retained only 2% of the total arsenic mass in their roots, its presence was a determining factor for arsenic retention in the wetland soil medium. CONCLUSION: Hence, planted wetlands might be a suitable option for treating As-contaminated water.
Show more [+] Less [-]Effect of Pb toxicity on leaf growth, antioxidant enzyme activities, and photosynthesis in cuttings and seedlings of Jatropha curcas L
2012
Shu, Xiao | Yin, LiYan | Zhang, QuanFa | Wang, Weibo
BACKGROUND: Cuttings and seedlings of Jatropha curcas L. were exposed to different regimes of lead (Pb) stress as Pb(NO3)2 at 0 (CK), 0.5, 1, 2, 3, and 4 mM kg−1 soil. OBJECTIVES: The effect of Pb treatment on the root length, tolerance index, photosynthetic pigments, photosynthetic activity, lipid peroxidation, and antioxidant enzyme was studied in a greenhouse pot experiment. RESULTS: The results showed that root lengths and tolerance index decreased with increase of Pb concentration, but tolerance index of cuttings was always lower than those of the seedlings. For cuttings, Pb treatment had a stimulating effect on chlorophyll content, carotenoid content, and superoxide dismutase (SOD) activity at low concentration and an inhibitory effect at higher concentration. For seedlings, SOD activity increased with increasing Pb concentration. In both seedlings and cuttings, Pb caused inhibition of leaf growth and photosynthesis, and induced the membrane damage which was more obvious in the cuttings. In comparison with the control, the dynamic tendency of catalase and perxidase activities in the leaves of Pb-stressed plants all ascended, and then declined. DISCUSSION: The increase in enzyme activities demonstrated that seedlings were more tolerant to Pb stress than cuttings. These results also indicate that the antioxidant system may play an important role in eliminating or alleviating the toxicity of Pb in J. curcas seedlings and cuttings. The accumulation of Pb increased in a concentration-dependent manner; however, its translocation from root to shoot was low. The cuttings accumulated significantly higher Pb in roots than seedlings.
Show more [+] Less [-]Combined biological processing and microfiltration in the treatment of unhairing wastewater
2012
Mlaik, Najwa | Bouzid, Jalel | Belbahri, Lassad | Woodward, Steve | Mechichi, Tahar
INTRODUCTION: The unhairing step, a part of the beamhouse process, is particularly polluting, generating an alkaline wastewater with high concentrations of organic and inorganic matter. The aim of this study was to evaluate the treatment of this industrial wastewater using a combination of biological and microfiltration processes. MATERIALS AND METHODS: The performance of the activated sludge system (AS) was evaluated under varying organic loading rate (OLR) from 0.9 to 3.4 kg chemical oxygen demand (COD) m−3 day−1 and decreasing hydraulic retention time (HRT) from 3 to 1.6 days. RESULTS: For an HRT of 3 days, the increase of OLR significantly affected the removal of organic matter. Therefore, the biological organic matter removal of unhairing wastewater decreased from 92% to 66% for COD and from 87 to 53% for biological oxygen demand (BOD5). GC-MS analyses showed that biological treatment of unhairing wastewater contributed to the removal of long chain fatty acids and their degradation products. Microfiltration of unhairing wastewater was performed using 0.2 μm pore-size membranes in tangential filtration. The highest removal efficiencies were obtained for bacteria (100%) and turbidity (98.4%) which confirmed the importance of the microfiltration step in treatment of unhairing wastewater. The result showed that the flux decay rate was greatest at the start of the microfiltration assay (90 L h−1 m2), becoming 60.7 L h−1 m2 after 32 min. CONCLUSION: This change indicated that fouling occurred rapidly once the membrane module was put into operation.
Show more [+] Less [-]Acute and chronic toxicity of benzotriazoles to aquatic organisms
2012
Seeland, Anne | Oetken, Matthias | Kiss, Aliz | Fries, Elke | Oehlmann, Jörg
PURPOSE: Resulting from their intensive use as corrosion inhibitors in aircraft deicing and anti-icing fluids (ADAF) and for silver protection in dishwasher detergents benzotriazoles (BTs) are widespread in European surface waters. The current study aimed on an ecotoxicological characterization of 1H-benzotriazole (1H-BT) and 5-methyl-1H-benzotriazole (5MBT). METHODS: Acute and chronic OECD guideline tests were conducted with primary producers (Desmodesmus subspicatus, Lemna minor) and two daphnia species (Daphnia magna, Daphnia galeata) to characterize the hazard of these chemicals. Additionally, the estrogenic activity of both BTs was analyzed in vitro using a recombinant yeast estrogen screen (YES). RESULTS: Both BTs revealed significant effects in acute and chronic experiments, but exhibited no estrogenic activity in the YES. The algal growth test displayed an inhibited cell number increase with effect concentration (EC) values of EC10 1.18 and 2.86 mg l-1 for 1H-BT and 5MBT, respectively. In the Lemna test, EC10 values were 3.94 mg l-1 (1H-BT) and 2.11 mg l-1 (5MBT). D. magna was also affected with EC50 (48 h) values of 107 mg l-1 for 1H-BT and 51.6 mg l-1 for 5MBT. D. galeata was more sensitive with an EC50 (48 h) of 14.7 mg 1H-BT l-1 and 8.13 mg 5MBT l-1. In the 21-day reproduction tests with D. magna, the EC10 for 5MBT was 5.93 mg l-1 while 1H-BT showed no adverse effects. D. galeata turned out to be more sensitive in the chronic study with EC10 values of 0.97 mg l-1 for 1H-BT and 0.40 mg l-1 for 5 MBT. CONCLUSION: Because BTs are regularly found in the aquatic environment at lower μg l-1 concentrations reflecting their persistence and poor elimination during wastewater treatment processes, a preliminary risk assessment was conducted. There is little indication that BTs pose a risk for aquatic ecosystems at current exposure levels during most of the year. However, it cannot be excluded that in winter with a higher usage of ADAFs environmental concentrations may well exceed the level that is considered safe for aquatic organisms.
Show more [+] Less [-]Isolation of a novel Pseudomonas sp from soil that can efficiently degrade polyethylene succinate
2012
Tribedi, Prosun | Sarkar, Subhasis | Mukherjee, Koushik | Sil, Alok K.
PURPOSE: Polyethylene succinate (PES) is a biodegradable synthetic polymer and therefore widely used as a base material in plastic industry to circumvent the environmental problems related with the non-biodegradability of other polymers like polyethylene. Till date only few organisms have been reported to have the ability to degrade PES. Therefore for better management of PES-related environmental waste, the present study is targeted towards isolating mesophilic organism(s) capable of more efficient degradation of PES. RESULTS: Strain AKS2 was isolated from soil based on survival on a selection plate wherein PES was used as sole carbon source. Ribotyping and biochemical tests revealed that AKS2 is a new strain of Pseudomonas. Scanning electron and atomic force microscopic analysis of the PES films obtained after incubation with AKS2 confirmed PES-degradation ability of AKS2, wherein an alteration in surface topology was observed. The kinetics of PES weight loss showed that AKS2 degrades PES maximally during its logarithmic growth phase at a rate of 1.65 mg/day. This degradation is mediated by esterase activity and may also involve cell-surface hydrophobicity. It has also been observed that AKS2 is able to degrade PES considerably even in the presence of glucose, which is likely to increase the bioremediation potential of this isolate. CONCLUSION: A new strain of Pseudomonas has been isolated from soil that is able to adhere to PES and degrade this polymer efficiently. This organism has the potential to be implemented as a useful tool for bioremediation of PES-derived materials.
Show more [+] Less [-]Influences of natural emission sources (wildfires and Saharan dust) on the urban organic aerosol in Barcelona (Western Mediterranean Basis) during a PM event
2012
van Drooge, Barend L. | Lopez, Jordi F. | Grimalt, Joan O.
The urban air quality in Barcelona in the Western Mediterranean Basin is characterized by overall high particulate matter (PM) concentrations, due to intensive local anthropogenic emissions and specific meteorological conditions. Moreover, on several days, especially in summer, natural PM sources, such as long-range transported Saharan dust from Northern Africa or wildfires on the Iberian Peninsula and around the Mediterranean Basin, may influence the levels and composition of the organic aerosol. In the second half of July 2009, daily collected PM10 filter samples in an urban background site in Barcelona were analyzed on organic tracer compounds representing several emission sources. During this period, an important PM peak event was observed. Individual organic compound concentrations increased two to five times during this event. Although highest increase was observed for the organic tracer of biomass burning, the contribution to the organic aerosol was estimated to be around 6 %. Organic tracers that could be related to Saharan dust showed no correlation with the PM and OC levels, while this was the case for those related to fossil fuel combustion from traffic emissions. Moreover, a change in the meteorological conditions gave way to an overall increase of the urban background contamination. Long-range atmospheric transport of organic compounds from primary emissions sources (i.e., wildfires and Saharan dust) has a relatively moderate impact on the organic aerosol in an urban area where the local emissions are dominating.
Show more [+] Less [-]Histopathological effects of carbaryl on testes of snake-eyed lizard, Ophisops elegans
2012
Cakici, Ozlem | Akat, Esra
BACKGROUND, AIM AND SCOPE: Due to their ecological niche and insectivore nature, lizards are of increased risk of exposure to pesticides in agricultural areas. In addition to their potential direct effects on non-target species, insecticides can also result in indirect impacts on lizard population by reducing their food source. Carbaryl is a common insecticide that is widely used in areas of Turkey that are home to a variety of reptiles. However, to date, little is known about the potential effects of the exposure of reptiles such as lizards or snakes to this pesticide. The aim of the study was to investigate toxic effects of carbaryl on the testes of snake-eyed lizard, Ophisops elegans that is common to regions in Turkey where Carbaryl is applied and that it can be easily cultured in the laboratory. MATERIAL AND METHODS: Adult male lizards were exposed to carbaryl once by oral gavage in concentrations of 2.5, 25 and 250 μg/g. After 96 h, lizards were euthanized and dissected. Histopathological changes were detected by randomly counting 100 tubules in each lizard. Seminiferous tubules were categorized as normal, sloughing and disorganized tubules. Diameters of tubules were also measured. The differences in histopathological changes and tubule diameters were compared for statistical significance by one-way ANOVA, using SPSS 16.0. RESULTS AND DISCUSSION: Histopathological changes were more prominent in medium- (25 μg/g) and high-dose (250 μg/g) groups than in the low-dose (2.5 μg/g) group. In the medium-dose group, the hexagonal appearance of most tubules disappeared, and they took on an oval shape. Sloughing was the characteristic tubule appearance of the medium group. In the high-dose group, significant increases in the number of disorganized tubules and prominence of haemorrhages was observed. CONCLUSION: Carbaryl caused histopathological defects on the testes of O. elegans, so it is clear that carbaryl affects male fertility in O. elegans.
Show more [+] Less [-]