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EU chemicals legislation requires the use of all available information for hazard and risk assessment before new tests on vertebrates are proposed or conducted. In this context, extrapolation approaches for avoiding chronic fish testing on the basis of existing data have been explored. Simple linear relationships and interspecies sensitivity ratios betweenDaphniaand fish were calculated and acute-to-chronic relationships and ratios were calculated for fish, taking into consideration the mode of action. The best fitted relationships for the prediction of chronic fish toxicity are obtained based on acute fish andDaphniadata. Chemicals acting by unspecific reactivity and non-polar narcosis give the strongest acute and chronicDaphnia-to-chronic fish relationship. With acute fish data, strong relationships are obtained for all mode of action.Daphniawas found to be more sensitive than fish to several aniline derivatives and pesticides acting through cholinesterase inhibition, and less sensitive than fish to known endocrine disruptors. Extreme (i.e. <1 or >100) interspecies sensitivity ratios were mainly evident for chemicals acting by polar narcosis and specific reactivity. The safety factor of 100 commonly applied in environmental risk assessment does not seem to be equally protective for each mode of action. [ABSTRACT FROM AUTHOR]

Moray eels (Gymnothorax species) from tropical waters have long been known to be high-risk species, and the consumption of particularly the viscera or ungutted eels can result in severe ciguatera (known as Gymnothorax or moray eel poisoning), characterized by prominent neurological features. In this review, the main objective was to describe the risk and severity of ciguatera caused by eating moray eels in different parts of the world. Moray eels can accumulate very high ciguatoxin (CTX) levels in the flesh and particularly the liver. Therefore, even the smaller ones can be toxic and the consumption of an average portion (particularly liver) can result in severe or fatal ciguatera. Moray eels (particularly when ungutted) must never be served in gatherings since they can cause mass poisoning because of their large sizes and high CTX levels. Apart from regulatory measures restricting or excluding access, the public should be repeatedly warned to avoid eating moray eels. [ABSTRACT FROM AUTHOR]

Background: Methylmercury (MeHg) is a highly toxic compound that traverses the blood–brain barrier with deleterious effects to the central nervous system. Exposure is generally through the ingestion of contaminated fish. Fish are a main source of MeHg. Goals and methods: The aim of this study was to determine the dependence of MeHg concentrations on fish species and age, the percentage of MeHg in total mercury (THg) and risk assessment depending on the size of fish. Assays of THg and MeHg were performed on the muscle tissues of 18 species of fish. Results: The investigations indicated there were differences in the mercury concentrations depending on fish size. THg and MeHg concentrations in the muscles of fish species that have a wide length distribution were strongly, positively correlated with fish length. However, concentrations of MeHg were strongly, positively correlated with those of THg in all the fish species investigated. Variation in the percentage share of MeHg in THg in the muscles of fish of large sizes was also noted within species, but this correlation was not noted in small-sized fish. The dose of MeHg in small-sized fish species was estimated and the risk posed to consumer health was assessed using mean MeHg concentrations determined for different fish species. Conclusions: For species of fish that occur within a wide length distribution, the dose of MeHg should be assessed separately in different length classes. Fish consumption of small-sized species poses no health risk. [ABSTRACT FROM AUTHOR]

Aeromonas hydrophila is a major pathogen in aquaculture in China; it is also an emerging pathogen in humans and animals. In recent years, several severe diseases, such as gastroenteritis, meningitis, and skin and soft tissue infections, have been found to be caused by A. hydrophila. Aerolysin and hemolysin are the most important virulence factors secreted by A. hydrophila. Therefore, new drugs targeted at these two toxins can be found in the therapy for A. hydrophila infections, reducing the usage of antibiotics. In this paper, we expressed and purified the aerolysin and hemolysin using a prokaryotic expression system. We found that aerolysin was more toxic than hemolysin, both in vitro and in vivo. The lethal dose ( LD50) of aerolysin and hemolysin was 0.4 and 2.3 µg per fish, respectively. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (17.78 ± 12.12 nm) were synthesized by the reduction of 0.5 M silver nitrate using formaldehyde as reducing and triethylamine as promoting and stabilizing agent. The particles were grain like agglomerates with spherical, centered-face cubic and crystalline in nature. The sample was highly pure with amine (NH) as associated and capping molecules. Further, the genotoxicity and oxidative stress of these particles were evaluated using Labeo rohita (L. rohita) as genetic model exposed (10-55 mg L-1 dose) through aquatic medium for 28 days. The cells were produced with micronuclei, fragmented, lobed and buds nuclei in dose dependent manner. The highest incidence of comet was recoded (27.34 ± 5.68) at 55 mg L-1 Ag-NPs and 14 days treatment. Then frequency was decreased to 22.65 ± 6.66% after 28 days due to complex repair mechanism. Moreover, the treatment also produces the oxidative stress and disturbs the level of GST in gill and liver tissue. There was a sharp decline in the activities of GST and this decrease of activity increase the MDA content. Further, the elevated level of GSH represents that the liver has started defensive mechanism against oxyraidcals. This study concluded, Ag-NPs are genotoxic in nature and produce micronuclei, comet cells and also induces oxidative stress in aquatic organisms. [ABSTRACT FROM AUTHOR]

In Australia, trace organic contaminants (TrOCs) and endocrine active compounds (EACs) have been detected in rivers impacted by sewage effluent, urban stormwater, agricultural and industrial inputs. It is unclear whether these chemicals are at concentrations that can elicit endocrine disruption in Australian fish species. In this study, native rainbowfish ( Melanotaenia fluviatilis ) and introduced invasive (but prevalent) mosquitofish ( Gambusia holbrooki ) were exposed to the individual compounds atrazine, estrone, bisphenol A, propylparaben and pyrimethanil, and mixtures of compounds including hormones and personal care products, industrial compounds, and pesticides at environmentally relevant concentrations. Vitellogenin (Vtg) protein and liver Vtg mRNA induction were used to assess the estrogenic potential of these compounds. Vtg expression was significantly affected in both species exposed to estrone at concentrations that leave little margin for safety (p < 0.001). Propylparaben caused a small but statistically significant 3× increase in Vtg protein levels (p = 0.035) in rainbowfish but at a concentration 40× higher than that measured in the environment, therefore propylparaben poses a low risk of inducing endocrine disruption in fish. Mixtures of pesticides and a mixture of hormones, pharmaceuticals, industrial compounds and pesticides induced a small but statistically significant increase in plasma Vtg in rainbowfish, but did not affect mosquitofish Vtg protein or mRNA expression. These results suggest that estrogenic activity represents a low risk to fish in most Australian rivers monitored to-date except for some species of fish at the most polluted sites. [ABSTRACT FROM AUTHOR]

Lethal concentration ( LC50) and sub-lethal effects of NO2-N on the endemic viviparous fishes Skiffia multipunctata (Pellegrin, 1911) ( SM; considered threatened under Mexican regulations) and Goodea atripinnis (Jordan, 1880) ( GA; without conservation status) were determined. LC50/96 hr values were 0.002 and 0.359 mg NO2-N/L for SM and GA, respectively. Sub-lethal exposure resulted in swelling of the gill epithelium, hyperplasia, fusion of the primary and secondary lamellae, erythrocyte pyknosis, and aneurysms with respiratory stress responses at 0.0012 and 0.244 mg NO2-N/L for SM and GA. The study demonstrates that sensitivity of both species is strongly related to the conservation status and acceptable nitrite concentrations, which are clearly below those permitted by the Mexican national water quality norm for wildlife preservation. Therefore, this norm is not adequate protection for these species, and where other threatened species may also be affected. Adequate criteria for nitrites in Mexican waters should include the data of all threatened endemic species. [ABSTRACT FROM AUTHOR]

Arsenic (As) is found in waters such as seawater, warm springs, groundwater, rivers, and lakes. In aquatic environments, As occurs as a mixture of arsenate and arsenite, with arsenate usually predominating. The unrestricted application of As pesticides, industrial activities, and mining operations has led to the global occurrence of soluble As above permissible levels of 0.010 mg/L. Continuous exposure of freshwater organisms including fish to low concentrations of As results in bioaccumulation, notably in liver and kidney. As a consequence As induces hyperglycemia, depletion of enzymatic activities, various acute and chronic toxicity, and immune system dysfunction. Here we review arsenic chemistry, the occurrence of arsenic in aquatic system, the transformation and metabolism of arsenic; arsenic bioaccumulation and bioconcentration; behavioral changes; and acute and other effects such as biochemical, immunotoxic, and cytogenotoxic effects on fish. [ABSTRACT FROM AUTHOR]

Fish venoms are often poorly studied, in part due to the difficulty in obtaining, extracting, and storing them. In this study, we characterize the cardiovascular and neurotoxic effects of the venoms from the following six species of fish: the cartilaginous stingrays Neotrygon kuhlii and Himantura toshi, and the bony fish Platycephalus fucus, Girella tricuspidata, Mugil cephalus, and Dentex tumifrons. All venoms (10-100 μg/kg, i.v.), except G. tricuspidata and P. fuscus, induced a biphasic response on mean arterial pressure (MAP) in the anesthetised rat. P. fucus venom exhibited a hypotensive response, while venom from G. tricuspidata displayed a single depressor response. All venoms induced cardiovascular collapse at 200 μg/kg, i.v. The in vitro neurotoxic effects of venom were examined using the chick biventer cervicis nerve-muscle (CBCNM) preparation. N. kuhlii, H. toshi, and P. fucus venoms caused concentration-dependent inhibition of indirect twitches in the CBCNM preparation. These three venoms also inhibited responses to exogenous acetylcholine (ACh) and carbachol (CCh), but not potassium chloride (KCl), indicating a post-synaptic mode of action. Venom from G. tricuspidata, M. cephalus, and D. tumifrons had no significant effect on indirect twitches or agonist responses in the CBCNM. Our results demonstrate that envenoming by these species of fish may result in moderate cardiovascular and/or neurotoxic effects. Future studies aimed at identifying the molecules responsible for these effects could uncover potentially novel lead compounds for future pharmaceuticals, in addition to generating new knowledge about the evolutionary relationships between venomous animals. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate and compare total mercury (Hg), selenium (Se), and Se:Hg molar ratios in fish muscles (phytophages n=3; benthophages n=32; predators n=5) and semiaquatic carnivores, including piscivores (the European otter n=8, the feral American mink n=7) and the omnivorous raccoon (n=37) from a riverine European ecosystem in a Se-deficient area. The Hg concentration in fish reached 0.337 μg/g dry weight, dw (0.084 μg/g wet weight, ww). We found significant differences among Hg levels in tested vertebrate groups (predators vs benthophages: 0.893 vs 0.281 μg/g; piscivores vs omnivores: 6.085 vs 0.566 μg/g dw). Fish groups did not differ in Se concentrations, with a mean value of 0.653 μg/g dw. Significant differences were revealed between Se levels in piscivorous and omnivorous carnivores (0.360 vs 0.786 μg/g dw, respectively). Fish Se:Hg molar ratio values were >2.2. Benthophages had higher the ratio than predators but similar to phytophages. Among carnivores, piscivores had much lower the ratio than raccoon (0.14 vs 3.75) but raccoon and fish medians did not significantly differ. We found almost two times higher Se levels in fish and raccoons compared to piscivores, possibly resulting from lower fish Se digestibility by piscivores in contrast to higher absorption of plant Se by many fish and omnivorous raccoons. Considering that a tissue Se:Hg molar ratio <1 may be connected with a Hg toxicity potential increase, we assume that piscivores in Se-deficient area are in worse situation and more exposed to Hg than fish and omnivores. [ABSTRACT FROM AUTHOR]

The ichthyotoxic dinoflagellate Cochlodinium polykrikoides poses a significant threat to the Korean finfish aquaculture industry, thus calling for effective mitigation strategies. We here report for the first time on investigations to assess the efficacy of routine application of clay to a naturally occurring Cochlodinium polykrikoides bloom off Namhae Island in South Korea during August-September 2015. Applications of conventional Korean loess reduced Cochlodinium cell concentrations from a maximum of 4600 mL −1 to levels considered safe for aquaculture operations (<1000 cells mL −1 ). However, at the same time, two clay application episodes increased ichthyotoxicity in water samples (measured by the gill cell line RTgill-W1 assay) by up to 32% compared to non-treated areas. Simulated laboratory culture experiments identified clay mediated Cochlodinium cell lysis as the probable cause. Lysed cells maintained cytotoxicity for up to 48 h (gill cell viability reduced to 39 ± 7% after 2.5 h exposure), but application of a finely-milled Korean loess completely eliminated ichthyotoxicity. Our results suggest that the fish-killing mechanism of Cochlodinium is comprised of both a stable (up to 48 h) and a transient fraction (decay within minutes). The latter indicates potential involvement of reactive oxygen species (ROS). We offer recommendations to fine-tune existing clay application regimes in Korean waters by focusing not on Cochlodinium cell removal, but on the adsorptive properties of clays to eliminate ichthyotoxicity. [ABSTRACT FROM AUTHOR]

A fast, sensitive and environmental-friendly method was developed to determine 13 organochlorine pesticides in fish tissue through gas chromatography with electron capture detection. Sample was extracted initially by acetonitrile and then concentrated through dispersive liquid–liquid microextraction based on solidification of floating organic droplet (DLLME–SFO). Dispersive solid phase extraction (d-SPE) was not a separate step but integrated to DLLME-SFO procedure. In order to separate the d-SPE sorbent, water and organic phase well, a modification to the glass centrifuge tube was made to achieving high centrifugal speed. The optimized method was validated with recoveries ranging from 88.1% to 121.2% (with relative standard deviations <15%) at three spiked levels for all of the pesticides. Good linearity was achieved at seven concentration levels from 6.25 to 625 μg L −1 , which corresponded to 0.001–0.100 mg kg −1 in the sample. The limits of quantification and the limits of detection for 13 OCPs ranged from 1.94×10 −3 to 4.93×10 −3 mg kg −1 and 6.50×10 −4 to 1.58×10 −3 mg kg −1 , respectively. The method was successfully applied to analyze real fish samples. [ABSTRACT FROM AUTHOR]

Pufferfish, Lagocephalus sceleratus, L. suezensis and L. spadiceus, are widely distributed Lessepsian species along the Turkish and other eastern Mediterranean coasts. L. sceleratus is considered one of the worst invasive species in the Mediterranean Sea and recently caused human intoxication by accidental consumption. Therefore, methods to assess pufferfish toxicity and accurately identify toxic pufferfish are important for food safety. Firstly, 20 specimens of L. sceleratus were collected from the eastern Mediterranean coasts of Turkey. Tetrodotoxin (TTX) content was determined among different tissues (muscle, liver, gonad, kidney, intestine and skin) by liquid chromatography-tandem mass spectrometry. All of the specimens contained TTX. The highest TTX concentration was detected in the ovary (80.0 µg TTX/g), followed by the intestine (48.8 µg TTX/g), kidney (34.0 µg TTX/g) and liver (25.4 µg TTX/g). The flesh and testis contained detectable amounts of TTX (3.4 µg TTX/g and 2.6 µg TTX/g, respectively). TTX analogs were also detected in the tissues, with 4,9-anhydro-5,6,11-trideoxyTTX and 5,6,11-trideoxyTTX being the major analog. A species-specific PCR method was developed to identify three species of genus Lagocephalus based on the nicotinamide adenine dinucleotide dehydrogenase subunit 2 or cytochrome oxidase subunit I regions of the mitochondrial DNA of L. sceleratus, L. suezensis, and L. spadiceus. The designed primers amplified only DNA of target species and not those of other fish and shellfish species. The species-specific PCR method successfully identified these pufferfish species and could be applied to thermally treated products of the pufferfish with only 1 ng of extracted DNA. [ABSTRACT FROM AUTHOR]

We study the non-parametric estimation of a continuous distribution functionFbased on the partially rank-ordered set (PROS) sampling design. A PROS sampling design first selects a random sample from the underlying population and uses judgement ranking to rank them into partially ordered sets, without measuring the variable of interest. The final measurements are then obtained from one of the partially ordered sets. Considering an imperfect PROS sampling procedure, we first develop the empirical distribution function (EDF) estimator ofFand study its theoretical properties. Then, we consider the problem of estimatingF, where the underlying distribution is assumed to be symmetric. We also find a unique admissible estimator ofFwithin the class of nondecreasing step functions with jumps at observed values and show the inadmissibility of the EDF. In addition, we introduce a smooth estimator ofFand discuss its theoretical properties. Finally, we expand on various numerical illustrations of our results via several simulation studies and a real data application and show the advantages of PROS estimates over their counterparts under the simple random and ranked set sampling designs. [ABSTRACT FROM AUTHOR]

The present study reports the isolation of Clostridium perfringens from samples comprising of freshwater fish and fish products from Kolkata city of India, and determining their genotypes and antibiogram profile. A total of 102 samples consisting of intestinal and gill samples from fresh water fish (n=69) and fish products including fish pickles, fish curry and fried fish (n=33) were collected randomly from retail shops and restaurants. On cultural isolation and biochemical characterization, 24 (23.52%) samples [17 (24.63%) from fresh water fish (n=69) and 07 (21.21%) from fish products (n=33)] were presumptively identified as C. perfringens positive. The genotyping of the recovered C. perfringens isolates was done by amplifying species specific 16S rRNA gene and four major lethal toxin genes viz., alpha toxin gene (cpa), beta toxin gene (cpb), epsilon toxin gene (εtx) and iota toxin gene (ιtx). Apart from these, enterotoxin gene (cpe) and beta2 toxin gene (cpb2) were also targeted. In PCR assays, all the 24 (100%) isolates [17 (70.83%) from fresh water fish and 07 (29.17%) from fish products] were found to harbor species specific 16S rRNA and cpa toxin gene, however, 17 (70.83%) cpa positive isolates [12 (70.58%) from fresh water fish and 05 (71.42%) from fish products] were also found to harbor additional cpb2 toxin gene, while none of the isolates were found to be positive for cpb, εtx, ιtx and cpe genes. Based on these results, all the isolates were confirmed as C. perfringens type A (containing only alpha toxin gene). On antibiotic sensitivity testing, 76.47% of the isolates were found to be multidrug resistant with ciprofloxacin and amoxicillin/clavulanic acid as being the most sensitive drugs. Report regarding isolation and molecular characterization of C. perfringens from fish and fish products especially from Kolkata does not exist as well as from other regions of India are very scanty. The present findings suggest that fish may be considered as a potential source of C. perfringens type A infection to human populations through food chain and the high antibiotic resistance observed may pose serious public health concerns. Further detailed molecular epidemiological and antibiogram studies are suggested for designing and adapting appropriate prevention and control strategies for countering this important pathogen and its food-borne zoonotic concerns. [ABSTRACT FROM AUTHOR]

In the past few decades, extensive application of azoxystrobin has led to great concern regarding its adverse effects on aquatic organisms. The objective of the present study was to evaluate the reproductive toxicity of azoxystrobin to zebrafish. After adult zebrafish of both sexes were exposed to 2, 20 and 200 μg/L azoxystrobin for 21 days, egg production, the fertilization rate, the gonadosomatic index (GSI) and hepatosomatic index (HSI), 17β-estradiol (E2), testosterone (T) and vitellogenin (Vtg) concentrations, and histological alterations in the gonads and livers were measured. Meanwhile, expression alterations of genes encoding gonadotropins and gonadotropin receptors ( fshb , lhb, fshr and lhr ), steroid hormone receptors ( era , er2b and ar ), steroidogenic enzymes ( cyp11a , cyp11b , cyp17 , cyp19a , cyp19b , hsd3b and hsd17b ) in the hypothalamic-pituitary-gonad (HPG) axis and vitellogenin ( vtg1 and vtg2 ) in the livers were also investigated. The results showed that reduced egg production and fertilization rates were observed at 200 μg/L azoxystrobin. In female zebrafish, reduced E2 and Vtg concentrations, decreased GSI, increased T concentrations, and histological alterations in the ovaries and livers were observed at 200 μg/L azoxystrobin, along with significant down-regulation of lhb , cyp19b , lhr , cyp19a , vtg1 and vtg2 , and up-regulation of cyp17 , hsd3b and hsd17b . In male zebrafish, increased E2 and Vtg concentrations, reduced T concentration and GSI, and histological alterations in the testes and livers were observed after exposure to 20 and 200 μg/L azoxystrobin, along with significant up-regulations of cyp19b , cyp11a , cyp17 , cyp19a , hsd3b and hsd17b , vtg1 and vtg2 . Moreover, cyp11a , hsd3b , cyp19a , vtg1 and vtg2 in male zebrafish were significantly up-regulated after treatment with 2 μg/L azoxystrobin. The results of the present study indicate that azoxystrobin led to reproductive toxicity in zebrafish and male zebrafish were more sensitive to azoxystrobin than female zebrafish. [ABSTRACT FROM AUTHOR]

Short-chain chlorinated paraffins (SCCPs) are ubiquitous in the environment and might cause adverse environmental and human health effects. Little is known about the relative toxicity of different SCCP compounds especially during development. The objective of this study was to characterize and compare effects of seven SCCP groups at environmentally relevant levels, using a zebrafish ( Danio rerio ) model. Observations on malformation, survival rates at 96 h post fertilization (hpf), and hatching rates at 72 hpf indicated that the C 10- groups (C 10 H 18 Cl 4 , 1,2,5,6,9,10-C 10 H 16 Cl 6 and C 10 H 15 Cl 7 ) were more toxic than the C 12- groups (C 12 H 22 Cl 4 , C 12 H 19 Cl 7 and 1,1,1,3,10,12,12,12-C 12 H 18 Cl 8 ) and Cereclor 63L. The C 10- groups were also more potent than C 12- groups and Cereclor 63L in decreasing thyroid hormone levels. Among the three compounds within the C 10- group, the compounds with less chlorine content had stronger effects on sub-lethal malformations but less effects on triiodothyronine (T3) and tetraiodothyronine (T4). Only C 10 H 18 Cl 4 significantly decreased the mRNA expression of tyr , ttr , dio2 and dio3 at a dose-dependent manner suggesting that the specific mode of actions differ with different congeners. The mechanisms of disruption of thyroid status by different SCCPs could be different. C 10 H 18 Cl 4 might inhibit T3 production through the inhibition effect on dio2 . These results indicate that SCCP exposure could alter gene expression in the hypothalamic-pituitary-thyroid (HPT) axis and thyroid hormone levels. The mechanisms of disruption of thyroid status by different SCCPs could be different. Our results on the relative developmental toxicities of SCCPs will be useful to reach a better understanding of SCCP toxicity supporting environmental risk evaluation and regulation and used as a guidance for environmental monitoring of SCCPs in the future. [ABSTRACT FROM AUTHOR]

Long-term effect assessments in ecotoxicological investigations are important, yet there is a lack of suitable exposure systems for these experiments that can be used for riverine species. A cost-efficient miniature circulatory system was developed that was evaluated for its applicability in long-term exposures in 2 stream-dwelling species: brown trout ( Salmo trutta) and an amphipod ( Gammarus roeseli). In an egg-to-fry exposure of S. trutta, the toxicity of 2 reverse osmosis concentrates was investigated as examples. Control hatching rate of yolk sac fry was 75 ± 7% and thus complies with the Organisation for Economic Co-operation and Development validity criterion (≥66%). The reverse osmosis concentrates did not impair the hatching rate in any tested concentration. In G. roeseli, mortality rates remained below 20% during a 21-d cultivation, fulfilling the common validity criterion in ecotoxicological testing. Mortality was significantly lower when the species was fed with conditioned alder leaves instead of an artificial shrimp food. Finally, a toxicity test on G. roeseli using copper as the test substance revealed median lethal concentration (LC50) values of 156 μg/L after 96 h and 99 μg/L after 264 h, which is in line with literature findings using other accepted exposure units. In conclusion, the miniature circulatory system provides a novel and cost-efficient exposure system for long-term investigations on riverine species that may also be applicable for other species of fishes and macroinvertebrates. Environ Toxicol Chem 2016;35:2827-2833. © 2016 SETAC [ABSTRACT FROM AUTHOR]

The need for alternative approaches to the use of vertebrate animals for hazard assessment of chemicals and pollutants has become of increasing importance. It is now the first consideration when initiating a vertebrate ecotoxicity test, to ensure that unnecessary use of vertebrate organisms is minimized wherever possible. For some regulatory purposes, the use of vertebrate organisms for environmental risk assessments has been banned; in other situations, the number of organisms tested has been dramatically reduced or the severity of the procedure refined. However, there is still a long way to go to achieve a complete replacement of vertebrate organisms to generate environmental hazard data. The development of animal alternatives is based not just on ethical considerations but also on reducing the cost of performing vertebrate ecotoxicity tests and in some cases on providing better information aimed at improving environmental risk assessments. The present Focus article provides an overview of the considerable advances that have been made toward alternative approaches for ecotoxicity assessments over the last few decades. Environ Toxicol Chem 2016;35:2637-2646. © 2016 SETAC [ABSTRACT FROM AUTHOR]

Jellyfish sting has become a worldwide issue of critical concern to human health and safety in coastal areas in recent decades. Cyanea nozakii is one of the dominant blooming species and dangerous stingers in China. However, it remains unclear how many and what types of toxins are present in the venom. So, we used a combined transcriptomics and proteomics approach to investigate the venom composition of jellyfish C. nozakii . In total 4,608,524 Illumina valid reads were obtained to de novo assemble to 40,434 unigenes in the transcriptomics analysis. And, a total of 311,635 MS/MS spectra with 12,247 unique MS/MS spectra were generated to 1556 homologous proteins in the proteomics analysis. 174 potential toxin proteins were identified, with 27 proteins homology to the toxins from venomous animals, including phospholipase A2, zinc metalloproteinase-disintegrin agkistin, serine protease inhibitor, plancitoxin-1, alpha-latrocrustotoxin-Lt1a, etc. This study described the transcriptomics and venom proteomics of jellyfish C. nozakii for the first time. Our findings provide a comprehensive understanding of the venom composition of C. nozakii . Furthermore, the results may also be very helpful for the discovery of novel bioactive proteins, as well as the development of effective treatments for jellyfish sting in the future. Biological significance Jellyfish Cyanea nozakii is one of the most dangerous stingers in the coast of china. Hundreds of thousands of people would be stung every year and victims suffered a severe pain, itch, swelling, inflammation, wheal and even more serious consequence. However, it remains unclear how many and what types of toxins are present as well as the relationship between the clinical symptoms and toxins. Our combined transcriptomics and proteomics findings can provide a comprehensive understanding of the venom composition of C. nozakii and will also be helpful for the development of effective treatments for jellyfish sting in the future. [ABSTRACT FROM AUTHOR]

Juveniles of Solea solea were sampled during the spring season in three consecutive years at a marine site by the mouth of the Ebre river. The aim was to assess if the extractive works from the toxic load upstream the river could be reflected on the health status of the fish living at the immediate sea. The biomarkers selected for the in vivo field study are commonly used as indicators of chemical exposures. They include activities of energy metabolism: lactate dehydrogenase (LDH) and citrate synthase (CS); neurotoxicity: cholinesterases (ChE); xenobiotic metabolism: cytochrome P450 (CYP)-dependent: EROD and BFCOD, carboxylesterase (CbE), glutathione S-transferase (GST) and uridine diphosphate glucuronyltransferase (UDPGT); and oxidative stress parameters such as catalase (CAT), glutathione reductase (GR) and glutathione peroxidase (GPX) as well as levels of lipid peroxidation (LPO). These biomarkers were mostly analysed in liver but also in gills and muscle depending on their particular tissue distribution and role. A complementary in vitro approach was also sought to see the capacity of common emerging contaminants (pharmaceuticals and personal care products; PPCPs) to interact with the liver microsomal detoxification system of the fish (EROD, BFCOD and CbE activities). The results indicated that in fish sampled in 2015 there was an enhancement in detoxification parameters (EROD, BFCOD and gill GR), muscular ChEs and gill CS, but a decrease in CbE activity and a marked oxidative stress situation (increased LPO and decreased CAT activity). Also, 4 out of the 10 PPCPs tested in vitro were able to interact with the CYP3A4 (BFCOD) enzymatic system while the lipid regulators simvastatin and fenofibrate inhibited CbE activity, as it occurs in higher vertebrates. The in vivo results support the use of a multibiomarker approach when assessing the disturbances due to chemical exposures, not only spatially but also over time, once the influence of other variables has been taken into consideration. The in vitro results highlight the importance of the CYP3A4 and CbE pathway in pharmaceutical metabolism, also in fish. [ABSTRACT FROM AUTHOR]

A coated copper sulfate algicide designed for controlled release of copper was evaluated for its effectiveness in controlling phytoplankton in hybrid catfish, ♀ Ictalurus punctatus × ♂ Ictalurus furcatus, ponds. Copper concentrations were greater in ponds receiving weekly treatments with copper sulfate crystals than in ponds in which the coated copper sulfate was suspended in porous bags and left in ponds during the study. However, the coated copper sulfate treatment provided a similar degree of phytoplankton control for a period of about 4 mo. Copper additions did not negatively affect catfish survival, production, or feed conversion in either the copper sulfate crystal treatment or in the coated copper sulfate treatment as compared with the control ( P > 0.05). Flavor scores for fish did not differ between control and treatments ( P > 0.05). The coated copper sulfate appeared to be a potentially effective method for controlling phytoplankton in aquaculture ponds. It would be easier to apply and require fewer applications, and the coated copper algicide would not present a fish toxicity issue that can arise from high copper concentration immediately following copper sulfate crystal treatment. [ABSTRACT FROM AUTHOR]

T-2 toxin (T-2) is a trichothecene-A-type mycotoxin produced by the fungus Fusarium spp., which can contaminate animal feed. It is toxic to many living cells especially the hepatocytes and bone marrow cells. The effects of dietary T-2 on growth, biochemical and immunity parameters, and histopathological changes in the hepatopancreas of white shrimp ( Litopenaeus vannamei ) were studied. Shrimp with an initial body weight of 3.5 ± 0.5 g were fed five diets (n = 50/group) containing 0, 0.5, 1.2, 2.4, or 4.8 mg kg − 1 T-2. Dietary exposure to T-2 significantly decreased shrimp growth rate and specific growth rate ( P < 0.5), but not the fat content, compared with the control group. Exposure to T-2 damaged the hepatopancreas microstructure in a dose-dependent manner and this may have contributed to a lower hemolymph albumin concentration and lower phenoloxidase activity. Total hemocyte counts and activity of hemolymph glutamic-pyruvic transaminase > glutamic-oxaloacetic transaminase and alkaline phosphatase enzymes increased initially in a dose-dependent manner but declined thereafter. This study showed that T-2 is a multi-organ toxin with effects on the hemolymph, immune system, and hepatopancreas of shrimp. Collectively, these effects may have contributed to the inhibition of growth and decreased survival rate leading to a lower yield and quality of shrimp meat with resultant economic loss. Statement of relevance It is proposed that hemolymph phenoloxidase enzyme activity could be used as a cheap non-specific biomarker for initial screening of shrimp exposed to even low T-2 toxin concentrations, instead of more expensive LC-MS/MS T-2 analysis — although a dose response was not evident at high exposure concentrations. [ABSTRACT FROM AUTHOR]

Effects of different cooking methods (microwave, dry-heating in a pan, oven, hot plate and barbecuing) and fat levels (lean and fatty) on the formation of heterocyclic aromatic amines (HCAs) of various fishes (salmon, mackerel, sardine, whiting, trout and sea bass) were investigated. Cooking treatment had very significant effect (p < 0.01) on water and pH, significant (p < 0.05) effect on total HCA content. In addition, pH was very significantly (p < 0.01) affected by fish species, while fish species had no significant effect (p > 0.05) on total HCA content. The total HCA content of the samples ranged between non-detectable levels and 5.72 ng/g. The highest total HCA content statistically belonged to barbecued samples. In addition, it was determined that the total HCA content of dry-heated salmon and sea bass in a pan was under the limit of detection of the HCAs. [ABSTRACT FROM AUTHOR]

Local communities in some Asian, African and American countries, use plant toxins in fish poisoning for fishing activities; however, the effects of this practice on the particular wild fish assemblages is unknown. This study was conducted with the aim to investigate the effects of fish poisoning using Tephrosia candida, on freshwater fish diversity and abundance in streams at the boundary of the World Natural Heritage site, Sinharaja Forest Reserve, Sri Lanka. A total of seven field trips were undertaken on a bimonthly basis, from May 2013 to June 2014. We surveyed five streams with similar environmental and climatological conditions at the boundary of Sinharaja forest. We selected three streams with active fish poisoning practices as treatments, and two streams with no fish poisoning as controls. Physico-chemical parameters and flow rate of water in selected streams were also measured at bimonthly intervals. Fish were sampled by electrofishing and nets in three randomly selected confined locations (6 x 2 m stretch) along every stream. Fish species were identified, their abundances were recorded, and Shannon-Weiner diversity index was calculated for each stream. Streams were clustered based on the Bray-Curtis similarity matrix for fish composition and abundance. Physico-chemical parameters of water were not significantly different among streams (P > 0.05). A total of 15 fish species belonging to four different orders Cypriniformes, Cyprinodontiformes, Perciformes and Siluriformes were collected; nine species (60%) were endemic, and six (40%) were native species. From these, 13 fish species were recorded in streams with no poisoning, while five species were recorded in streams where poisoning was practiced. Four endemic and one native fish species were locally extinct in streams where fish poisoning was active. Fish abundance was significantly higher in control streams (32-39/m2) when compared to treatment streams (5-9/m2) (P < 0.05). We concluded that fish poisoning with T. candida may have resulted in a significant reduction in species richness, total abundance and Shannon-Weiner diversity index of fish species in the studied streams at the boundary of Sinharaja forest. We recommend that this fishing practice should be strictly regulated, and to inform local communities about the legal status of fish poisoning, its consequences and the importance of fish diversity for local livelihoods and conservation purposes. Rev. Biol. Trop. 64 (3): 1129-1141. Epub 2016 September 01. [ABSTRACT FROM AUTHOR]

Chemical functionalization to tailor surface properties of nanomaterials (NMs) is expected to broaden their scope of potential applications but may also be used to modify NM toxicity. We have examined the physicochemical properties of single-walled carbon nanotubes (SWCNTs) with varying degrees of carboxylic acid group functionalization, two types of lignin-wrapped SWCNTs, as well as nonfunctionalized SWCNTs. Zebrafish ( Danio rerio ) embryos were exposed to 1, 10, 50, 100 or 200 mg/L functionalized and nonfunctionalized SWCNTs for up to 72 h; measured endpoints included survival, hatching success, and alteration in gene expression. We have also characterized carboxylated cellulose nanocrystals (CNCs) and examined their effects both in vivo using zebrafish and in vitro using three channel catfish ( Ictalurus punctatus ) cell lines. While nonfunctionalized SWCNTs did not affect survival or hatch of embryos, carboxylic acid functionalized SWCNTs accelerated hatching and lignin-wrapped SWCNTs both decreased survival and delayed hatch at all time points tested. Carboxylated CNC exposure decreased the viability of 1G8 and 28S.3 catfish cells. We suggest that surface functionality affects SWCNT characteristics and plays a key role in determining their toxicity. [ABSTRACT FROM AUTHOR]

Chemical induced changes in fish biomarkers vitellogenin (VTG), secondary sex characteristics (SSC), and sex ratio indicate modes/mechanisms of action (MOAs) of EAS (estrogen, androgen and steroidogenesis) pathways. These biomarkers could be used for defining MOAs and the causal link between MOAs and adverse effects in fish for the identification of endocrine disrupting chemicals (EDCs). This paper compiled data sets of 150 chemicals for VTG, 57 chemicals for SSC and 38 chemicals for sex ratio in fathead minnow, medaka and zebrafish. It showed 1) changes in fish biomarkers can indicate the MOAs as anticipated; 2) in addition to EAS pathways, chemicals with non-EAS pathways induced changes in fish biomarkers; 3) responses of fish biomarkers did not always follow the anticipated patterns of EAS pathways. These responses may result from the interaction of chemical-induced multiple MOAs and confounding factors like fish diet, infection, culture conditions, general toxicity and stress response. The complex response of fish biomarkers to a chemical of interest requires EDC testing at multiple biological levels. Interpretation of fish biomarker data should be combined with relevant information at different biological levels, which is critical for defining chemical specific MOAs. The utility of fish biomarker data for identification, classification, PBT assessment, risk assessment, and testing of EDCs in the regulatory context was discussed. This paper emphasizes the importance of fish biomarker data in the regulatory context, a weight of evidence approach for the interpretation of fish biomarker data and the need for defining levels of evidence for the identification of EDCs. [ABSTRACT FROM AUTHOR]

Metal bioaccumulation and induction of biomarkers such as lipid peroxidation (LPO), superoxide dismutase (SOD), catalase (CAT), glutathione S transferase (GST), reduced glutathione (GSH) and DNA damage are potential indicators of stress in Channa punctatus exposed to effluents. In canal water, receiving thermal power plant discharges, Fe and Ni concentrations exceeded the recommended guidelines set by the United Nations Environment Programme Global Environment Monitoring System (UNEPGEMS). Fe was highly bioavailable and accumulated in all organs (liver, kidney, muscle and integument). The highest metal pollution index (MPI) value of 41.2 was observed in kidney and the lowest 13.5 in muscle tissue. LPO, SOD, CAT and GST levels were significantly higher in liver and kidney, whereas GSH levels declined significantly compared to fish from the reference site. Concomitant damage to DNA was observed with significantly higher mean tail length in the exposed fish gill cells (26.5 µm) and in liver (20.8 µm) compared to reference fish. Therefore, it can be concluded that the thermal power plant effluent had the potential to cause oxidative stress and DNA damage in C. punctatus . [ABSTRACT FROM AUTHOR]

The present study is motivated by the increasing demand to consider internal partitioning into tissues instead of exposure concentrations for the environmental toxicity assessment. To this end, physiologically based pharmacokinetic (PBPK) models can be applied. We evaluated the variation in accuracy of PBPK model outcomes depending on tissue constituents modeled as sorptive phases and chemical distribution tendencies addressed by molecular descriptors. The model performance was examined using data from 150 experiments for 28 chemicals collected from US EPA databases. The simplest PBPK model is based on the “ K ow -lipid content” approach as being traditional for environmental toxicology. The most elaborated one considers five biological sorptive phases (polar and non-polar lipids, water, albumin and the remaining proteins) and makes use of LSER (linear solvation energy relationship) parameters to describe the compound partitioning behavior. The “ K ow -lipid content”-based PBPK model shows more than one order of magnitude difference in predicted and measured values for 37% of the studied exposure experiments while for the most elaborated model this happens only for 7%. It is shown that further improvements could be achieved by introducing corrections for metabolic biotransformation and compound transmission hindrance through a cellular membrane. The analysis of the interface distribution tendencies shows that polar tissue constituents, namely water, polar lipids and proteins, play an important role in the accumulation behavior of polar compounds with H-bond donating functional groups. For compounds without H-bond donating fragments preferable accumulation phases are storage lipids and water depending on compound polarity. [ABSTRACT FROM AUTHOR]

Fish venom remains a virtually untapped resource. There are so few fish toxin sequences for reference, which increases the difficulty to study toxins from venomous fish and to develop efficient and fast methods to dig out toxin genes or proteins. Here, we utilized Chinese yellow catfish (Pelteobagrus fulvidraco) as our research object, since it is a representative species in Siluriformes with its venom glands embedded in the pectoral and dorsal fins. In this study, we set up an in-house toxin database and a novel toxin-discovering protocol to dig out precise toxin genes by combination of transcriptomic and proteomic sequencing. Finally, we obtained 15 putative toxin proteins distributed in five groups, namely Veficolin, Ink toxin, Adamalysin, Za2G and CRISP toxin. It seems that we have developed a novel bioinformatics method, through which we could identify toxin proteins with high confidence. Meanwhile, these toxins can also be useful for comparative studies in other fish and development of potential drugs. [ABSTRACT FROM AUTHOR]

The jellyfishes of the genus Chrysaora are present in all of the world's oceans, but the toxicity of their venoms has not yet been thoroughly characterized. The zebrafish as a toxicology model can be used for general toxicity testing of drugs and the investigation of toxicological mechanisms. The aim of this study was to evaluate the effect of crude venom from jellyfish Chrysaora sp. , a species of jellyfish observed in the tropical lagoons of the Gulf of Mexico, on the zebrafish Danio rerio . Juvenile zebrafish were injected with different concentrations of venom from Chrysaora sp. via intraperitoneal and subcutaneous injections. The effects of the venom were determined by histopathological analysis and through the measurement of hemolytic and phospholipase A 2 activities. The crude venom was examined by SDS-PAGE. The effect of sublethal concentrations of crude venom from Chrysaora sp. on D. rerio was hemorrhaging in the eyes, while the histopathological analysis demonstrated that the primary organs targeted were the pseudobranch, which displayed hyperemia, and the gill, which displayed hyperplasia and hypertrophy. The blood analysis exhibited hemolysis, nuclear abnormalities, and echinocytes by the action of phospholipase A 2 , which was determined to have 596 units of activity/mg of protein in the venom. The crude venom has proteins with molecular weights ranging from 250 to 6 kDa, with more density in the bands corresponding to 70, 20 and 15 kDa. The venom of Chysaora sp . caused disturbances in circulation associated with vascular dilation due to the localized release of inflammatory mediators. The hemolysis of erythrocytes was caused by the action of phospholipase A 2 . These findings not only provide an excellent study model but also have a great pharmacological potential for designing new drugs and for the elucidation of the mechanisms of action of and treatment against stings. [ABSTRACT FROM AUTHOR]

This research provides an evaluation of the quality and health status of some locally abundant fish species, usually otter-trawl bycatch species. The study was conducted in the southern and eastern Spanish Mediterranean coast. Mean concentration of heavy metals in muscle and parasitisation indices showed moderate levels. Higher lead concentration was found in fish from the western Alboran and arsenic, cadmium and mercury were more present on fishes from the eastern Alboran area, although most species analysed contain moderate levels of heavy metals in muscle. Concerning parasitisation, F. Anisakidae nematodes were present in all the species, except sardine. Only mercury showed a positive relationship with parasitisation. We also considered three feeding guilds. Metal mean concentrations were higher in benthivores and more littoral fishes. Pelagic planktivores species are the healthiest and the more suitable for consumers from the sanitary point of view. [ABSTRACT FROM AUTHOR]

The goal of the current study was to evaluate different genotoxicity tools in order to assess a marine protected area (MPA) affected by former mining activities and urban settlements. A catfish ( Cathorops spixii ) was analyzed for genotoxic effects at the (i) molecular and at the (ii) chromosomal levels. Through factor analysis, genotoxicity was found to be linked to levels of metals bioaccumulated and PAH metabolites in the bile. Micronucleus and nuclear alteration were less vulnerable to the effects of confounding factors in mildly contaminated areas since they were more frequently associated with bioaccumulated metals than the DNA analysis. The different genotoxicity responses allowed for the identification of sources of pollution in the MPA. This approach was important for detecting environmental risks related to genotoxic contaminants in a mildly contaminated MPA. [ABSTRACT FROM AUTHOR]

Environmental management decisions at mercury-contaminated sediment sites are predicated on the understanding of risks to various receptors, including fish. Toxicity reference values (TRVs) for interpreting risks to fish have been developed to assess mercury concentrations in fish or fish prey. These TRVs were systematically evaluated based on several lines of evidence. First, their conceptual basis and specific derivation were evaluated, including a close review of underlying toxicity studies. Second, case studies were reviewed to investigate whether TRVs are predictive of effects on fish populations in the field. Third, TRVs were compared with available information regarding preindustrial and present-day background concentrations of mercury in fish. The findings show that existing TRVs are highly uncertain, because they were developed using limited data from studies not designed for TRV derivation. Although field studies also entail uncertainty, several case studies indicate no evidence of adverse effects despite mercury exposures that exceed the available TRVs. Some TRVs also fall within the range of background mercury concentrations in predatory or prey fish. Lack of information on the selenium status of mercury-exposed fish is a critical confounding factor, and the form of methylmercury used in toxicity testing may also contribute to differences between TRV-based predictions and field observations of mercury effects on fish. On balance, the available information indicates that several of the TRVs reviewed are lower than necessary to protect fish populations. The 20% effect concentration from a previously published dose-response analysis appears closer to an effect threshold, based on available laboratory data. Additional research is needed to provide a stronger basis to establish dose-response relationships for mercury effects on fish. Environ Toxicol Chem 2016;35:529-549. © 2016 SETAC [ABSTRACT FROM AUTHOR]

Investigations on the relationship of toxicities between species play an important role in the understanding of toxic mechanisms to environmental organisms. In this paper, the toxicity data of 949 chemicals to fish and 1470 chemicals to V. fischeri were used to investigate the modes of action (MOAs) between species. The results show that although there is a positive interspecies correlation, the relationship is poor. Analysis on the excess toxicity calculated from toxic ratios (TR) shows that many chemicals have close toxicities and share the same MOAs between the two species. Linear relationships between the toxicities and octanol/water partition coefficient (log KOW) for baseline and less inert compounds indicate that the internal critical concentrations (CBRs) approach a constant both to fish and V. fischeri for neutral hydrophobic compounds. These compounds share the same toxic mechanisms and bio-uptake processes between species. On the other hand, some hydrophilic compounds exhibit different toxic effects with greatly different log TR values between V. fischeri and fish species. These hydrophilic compounds were identified as reactive MOAs to V. fischeri, but not to fish. The interspecies correlation is improved by adding a hydrophobic descriptor into the correlation equation. This indicates that the differences in the toxic ratios between fish and V. fischeri for these hydrophilic compounds can be partly attributed to the differences of bioconcentration between the two species, rather than the differences of reactivity with the target macromolecules. These hydrophilic compounds may more easily pass through the cell membrane of V. fischeri than the gill and skin of fish, react with the target macromolecules and exhibit excess toxicity. The compounds with log KOW > 7 exhibiting very low toxicity (log TR < –1) to both species indicate that the bioconcentration potential of a chemical plays a very important role in the identification of excess toxicity and MOAs. [ABSTRACT FROM AUTHOR]

Coal tar sealcoats applied to asphalt surfaces in North America, east of the Continental Divide, are enriched in petroleum-derived compounds, including polycyclic aromatic hydrocarbons (PAHs). The release of PAHs and other chemicals from sealcoat has the potential to contaminate nearby water bodies, reducing the resiliency of aquatic communities. Despite this, relatively little is known about the aquatic toxicology of sealcoat-derived contaminants. We assessed the impacts of stormwater runoff from sealcoated asphalt on juvenile coho salmon (Oncorhynchus kisutch) and embryo-larval zebrafish (Danio rerio). We furthermore evaluated the effectiveness of bioretention as a green stormwater method to remove PAHs and reduce lethal and sublethal toxicity in both species. We applied a coal tar sealcoat to conventional asphalt and collected runoff from simulated rainfall events up to 7 months postapplication. Whereas sealcoat runoff was more acutely lethal to salmon, a spectrum of cardiovascular abnormalities was consistently evident in early life stage zebrafish. Soil bioretention effectively reduced PAH concentrations by an order of magnitude, prevented mortality in juvenile salmon, and significantly reduced cardiotoxicity in zebrafish. Our findings show that inexpensive bioretention methods can markedly improve stormwater quality and protect fish health. [ABSTRACT FROM AUTHOR]

Toxicological evaluation of Clarias gariepinus from bitumen-polluted River Oluwa, Nigeria, was carried out in furtherance of studies on the environmental impacts of the bitumen exploration in Ondo State, Nigeria. Samples were taken from three different (two polluted and one as control) sites. The effect of changes in monthly seasonal flow rate was assessed for the sites of study. Blood plasma clinical-chemical parameters (BCCPs) and histological changes/lesions in various organs were evaluated as markers of pollution in the fish blood using standard methods. The result of the physicochemical properties of water from the sampling points revealed some of the values conforming to approved standards while others showed deviation. Significant differences were found in the blood and histological endpoints between the control and the polluted sites as well as between the two seasons evaluated across the sites. The public health implications of consuming this fish are fully discussed. [ABSTRACT FROM AUTHOR]

The present study was conducted to reveal the concentrations and patterns of organochlorines [i.e., organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs)] in freshwater fish species collected from four ecologically important sites of the Indus River i.e., Taunsa (TAU), Rahim Yar Khan (RYK), Guddu (GUD) and Sukkur (SUK). In the fish muscle tissues, concentrations of 15 OCPs (∑ 15 OCPs) and 29 PCBs (∑ 29 PCBs) varied between 1.93–61.9 and 0.81–44.2 ng/g wet weight (ww), respectively. Overall, the rank order of OCs was DDTs > PCBs > hexachlorocyclohexanes (HCHs) > chlordanes (CHLs). The patterns of PCBs showed maximum contribution of tri-CBs (59%). Ratios of individual HCH and DDT analytes contributing to the summed values indicated both recent and past use of these chemicals in the region, depending upon fish species. To assess the associated health risks, carcinogenic and non-carcinogenic risks were calculated through hazard ratios (HRs). For carcinogenic risk, HR was > 1 at both 50th and 95th percentile concentrations, suggesting that the daily exposure to OCPs and PCBs yields a lifetime cancer risk of 1 in a million. HR for non-cancerous risk was < 1 at both the percentiles, signifying no adverse effect by OCs exposure in native population. [ABSTRACT FROM AUTHOR]

Ecotoxicological effects of industrial chemicals (Rig wash, Oil eater, Nalco, Glycol?) and pesticides (Propoxur, Deltamethrin, Atrazine, Furadan) on Tilapia guineensis (fish) and Aporrectodea longa (earthworms) were tested using the Organisation for Economic Cooperation and Development (OECD) # 203 and 207 protocols. The water and soil ratings indicate that the test chemicals were toxic to the organisms. The estimated 96 hour lethal concentration LC50 values for Rig wash, Oil eater, Nalco EC1304A/COT 505, Glycol, Propoxur, and Deltamethrin were 26.34±0.46, 6.02±0.30, 3.07±0.14, 1.31±0.01, 20.91±0 and 0.01±0 mg/l respectively. In the earthworm bioassay, the estimated 14-day LC50 values for Rigwash, Oil eater, Nalco EC1304A/COT 505, Glycol, Atrazine and Furadan were 80.05±3.5, 151.55±10.7, 172.63±14.2, 63.72±2.43, 4.97±0 and 0.29±0 mg/kg respectively. Safety factors are arbitrarily built in around the LC50 values in order to arrive at environmentally tolerable concentrations. The concentration of a chemical in the receiving environment should not exceed 10% of the LC50. The organisms exposed to the test chemicals showed significant difference when compared with the levels measured in the control group. The observed sensitivity of the test organisms to the chemicals indicates that adherence to standard safety limits/measures should be maintained during use and disposal of hazardous chemicals. This would ensure that the biotic components of the Nigerian Niger Delta ecosystem are prudently protected. [ABSTRACT FROM AUTHOR]

Cytochalasin B (CB) has been used to induce tetraploidy in oysters since the practice began in 1993. However, CB is toxic and presents health risks to hatchery workers who administer the treatment. 6-dimethylaminopurine (6-DMAP) is also an effective cytokinetic inhibitor, and does not carry the health risks of CB. We examined the relative effectiveness of 6-DMAP vs CB for producing tetraploids in the Eastern oyster ( Crassostrea virginica ). Survival and yield of tetraploids varied widely among the 15 experiments. Larvae resulting from 6-DMAP treatment had higher survival in 11 of the 14 trials on day two and day six/seven. For yield of tetraploids, 10 of 13 6-DMAP treatments had higher proportions of tetraploids on day two and at the second sampling – day six, seven, or nine – 7 of 10 had higher proportions of tetraploids. Tetraploid spat were obtained from the majority of surviving cultures. Based on these results, 6-DMAP can effectively replace CB for inducing polyploidy in C. virginica , and probably other Crassostrea spp. , due to the success of the treatment, the ease of application, and the reduction in health risk to hatchery workers. This study set the precedent for the use of 6-DMAP on C. virginica and established a new procedure for inducing tetraploids using triploid eggs. It might be possible to refine the treatment to further optimize yield of tetraploids. Statement of relevance In this manuscript we report a novel method of inducing tetraploid Crassostrea virginica from triploid eggs using 6-dimethylaminopurine. We compare the efficiency of cytochalasin B and 6-dimethylaminopurine for tetraploid induction. We also report the expected fecundity of triploid C. virginica females. The method of tetraploidy induction we report here will likely be useful for inducing tetraploidy in other Crassostrea spp. [ABSTRACT FROM AUTHOR]

The extensive use of malathion, an organophosphate pesticide, raises the possibility of its undesirable toxicity to non-target organisms. Agricultural run-off and vector control sprays are the major sources of exposure to this pesticide for aquatic organisms. Some earlier studies have reported the presence of malathion at concentrations ranging from 18.12 μg/L to 105.2 μg/L in various water samples. In this study, we have tested the hypothesis that these sub-lethal yet environmentally significant concentrations of malathion has serious toxicological implications on the fingerlings of Labeo rohita. Exposure to increasing concentration of malathion (10, 50 and 100 μg/L) was reflected in the serum concentration of the pesticide and also in the inhibition of acetylcholinesterase activity in fish brains. Increased abnormalities in liver function test coupled with a rise in the oxidative stress response were observed in gills, liver and kidney. However, the increase in antioxidant enzyme activities like superoxide dismutase and glutathione-S-transferase by malathion exposure suggested a hormetic response. Tissue injury due to malathion was evident from the morphological and nuclear anomalies in the H-E stained sections of gill, liver and kidney. Cell cycle analysis of these organs further fortified the histopathological findings. This study elucidates the sub-lethal toxicity of environmentally relevant malathion concentrations on Labeo rohita which indicates the potential health hazard posed to human beings consuming this fish. This calls for careful application of malathion in areas adjoining to inland fisheries. [ABSTRACT FROM AUTHOR]

Physiological stress and DNA damage inPelteobagrus fulvidracoinduced by continuous exposure to cadmium at concentrations of 170 and 1700 µg/L for up to 28 days was evaluated. The activities of acetylcholinesterase and monoamine oxidase in brain tissue, Na+-K+-ATPase and glutathione in gill tissue, and superoxide dismutase and catalase in liver tissue were measured. In studying random amplified polymorphic DNA to evaluate cadmium-induced hepatic genotoxicity, both the appearance of new bands and the disappearance of existing bands were observed, as well as increased levels of monoamine oxidase and Na+-K+-ATPase and decreased activities of antioxidant enzymes. The results suggest that continuous exposure to cadmium at the studied levels can induce biochemical and physiological changes and DNA damage inP. fulvidraco. [ABSTRACT FROM AUTHOR]

The present study determined concentrations of estrogenic bisphenol A (BPA), nonylphenol, octylphenol (4-tert-octylphenol), butylphenol (4-tert-butylphenol), and progestogenic norethindrone by liquid chromatography-tandem mass spectrometry in bile extracts from field fish from the Xin'an River and market fish in Shanghai, China. Compared with the field fish, endocrine disrupting chemical (EDC) concentrations in market fish bile were at relatively high levels with high detectable rates. The average concentrations of BPA, nonylphenol, 4-tert-octylphenol, 4-tert-butylphenol, and norethindrone in field fish bile were 30.1 µg/L, 203 µg/L, 4.69 µg/L, 7.84 µg/L, and 0.514 µg/L, respectively; in market fish bile they were 240 µg/L, 528 µg/L, 76.5 µg/L, 12.8 µg/L, and 5.26 µg/L, respectively; and in the surface water of Xin'an River they were 38.8 ng/L, 7.91 ng/L, 1.98 ng/L, 2.66 ng/L, and 0.116 ng/L, respectively. The average of total estrogenic activity of river water was 3.32 ng/L estradiol equivalents. High bioconcentration factors (BCFs) were discovered for all 5 EDCs (998-fold) in field fish bile. Furthermore, the authors analyzed the BCF value of BPA in fish bile after 30-d exposure to environmentally relevant concentrations of BPA in the laboratory, and the analysis revealed that BCF in fish bile (BCFFish bile) changed in an inverse concentration-dependent manner based on the log10-transformed BPA concentration in water. Strikingly, the data from the field study were well fitted within this trend. The data together suggested that analysis of fish bile extracts could be an efficient method for assessing waterborne EDCs exposure for aquatic biota. [ABSTRACT FROM AUTHOR]

Even though jellyfish sting is common today, its first aid guideline has never been clear enough in a scientific point of view and the use of vinegar appears to be not accepted in common throughout the world. In the present study, to develop rational first aid guidelines for the stings of Nemopilema nomurai (scyphozoa) and Carybdea mora (cubozoa), the modulatory effects of various kinds of rinsing solutions have been assessed on nematocyst discharge and human skin tests. Among the solutions tested, vinegar (4% acetic acid) immediately caused significant nematocyst discharge in N. nomurai but not in C. mora . On the other hand, ethanol (70%) notably stimulated nematocyst discharge in C. mora and relatively less in N. nomurai . Moreover, isopropanol, a widely used solvent in pharmaceutical products, caused extensive nematocyst discharges in both N. nomurai and C. mora . Whereas, seawater did not elicit any nematocyst discharge in both jellyfish species. In human skin test, the rinsing with seawater also ameliorated the stinging-associated symptoms (pain and redness) in C. mora as well as N. nomurai . From this study, seawater appears not to induce any nematocyst discharge and can be safely used as a first aid rinsing solution for the jellyfish stings. [ABSTRACT FROM AUTHOR]

The paper reviews scientific and practical aspects of research on the metabolism of nitrates into nitrate (nitrite) reductase in the nitric oxide cycle in fish under hypoxic conditions. Literature data are given about enzymes involved in nitrate reductase reactions and how oxygen shortage affects their activity. The environmental factors that may participate in the processes of nitrate reduction to nitrites as well as the ones which may influence the kinetics of nitrate in fishes are considered. Examined results indicate that certain components of the conservative L-arginine-dependent nitric oxide cycle pass in a number of vertebrate animals. Then, the contour cycle of nitric oxide in the fish shows a wide range of diversity which is represented by phylogenetically ancient biochemical mechanisms of nitrite (nitrate) reductase. First of all, the presence or absence of hemoglobin is distinguished. Secondly, a wider range of expression of different myoglobin isoforms appears. Furthermore, the kinetics of nitrates in fish is distinctly dependent on abiotic environmental factors. The analysis of the literature confirms the thesis that nitrates are an important substrate for the nitrate (nitrite) reductase loop cycle of nitric oxide in fishes. Secondly, their role in the compensation of arginineindependent NO synthesis increases with decreasing oxygen levels in the environment. Thirdly, the provided research results are a basis for indicating xanthine oxidase and possibly the microflora of the digestive system as the basic units of the nitrate reductase system in the body of fish. The practical aspect of the question, in our opinion, is the most meaningful presence of numerous studies that emphasize the need to find physiological reactions that precede the formation of pathological changes induced by the influence of combined effects of nitrates and hypoxia on the organism of fish. [ABSTRACT FROM AUTHOR]

In the paper first the two main learning strategies of the artificial neural networks (ANNs), the error-back propagation (EBP) and Kohonen self-organizing maps (SOM) are briefly described. Next, two nonstandard network layouts of the ANNs (bottle-neck and pyramidal decision tree) one for each of both learning strategies are suggested. In the last part, the use of counter-propagation (CP) ANN for handling chemical structures in QSAR modeling, classification and clustering is discussed. These concepts are of particular interest for the computer-aided drug research and in computer-aided toxicology. In the case study the results of fish toxicity research are described. [ABSTRACT FROM AUTHOR]

The composition of major hexabromocyclododecane (HBCD) diastereoisomers, i.e. α-, β-, and γ-HBCDs, in marine biota is different from that of the commercially available form (technical HBCD), which is used extensively for toxicological studies. To properly evaluate the impact of HBCDs, the embryos of Oryzias melastigma were used to examine the developmental toxicity of the individual diastereoisomers. Results showed that HBCD diastereoisomers at the environmentally realistic concentrations in the embryos induced malformation rate and heartbeat, and caused the appearance of apoptotic heart. In addition, α-, β-, and γ-HBCDs had similar potency to stimulate the generation of reactive oxygen species, consequently leading to apoptosis in O . melastigma embryos. The order of the developmental toxicity of α-, β-, and γ-HBCDs in O . melastigma embryos was different from that in zebrafish embryos studied previously, which highlighted the importance of using species from both fresh and salt water for toxicity assessment. [ABSTRACT FROM AUTHOR]

The objective of this study was to identify and to apply appropriate biotests having the advantages of being highly sensitive, easy to run, relatively inexpensive and able to substitute fish toxicity tests due to ethical reasons of animal welfare. To perform an ecotoxicological assessment of industrial wastewaters, different microbiotests were conducted to substitute the fish toxicity test withLebistes reticulatusthroughVibrio fischeri, Thamnocephalus platyurus, Daphnia magna,Lemna minorandLepidium sativumrepresenting different trophic levels in the aquatic and terrestrial ecosystems. Also, Algaltox FTMwithPseudokirchneriella subcapitataand Protox FTMwithTetrahymena thermophilatests were carried out. However, they could not be applied successfully for the wastewater samples. Wastewater samples from seven different industrial zones comprising different industries were subjected to characterization through measuring their physical–chemical parameters and their toxicity versus the above-mentioned organisms.T. platyurus,D. magnaandL. reticulatuswere the most sensitive test organisms investigated for the wastewaters. Considering toxic unit values, generally wastewater samples were toxic according to Thamnotox FTM, Daphtox FTMand fish toxicity tests. As an important outcome, it was concluded that Daphtox FTMand Thamnotox FTMcould be a good alternative for the fish toxicity test, which is so far the sole toxicity test accepted by the Turkish Water Pollution Control Regulation. [ABSTRACT FROM AUTHOR]

Gambierdiscus excentricus is an epibenthic dinoflagellate able to produce ciguatoxin and maitotoxin-like compounds that are responsible for ciguatera fish poisoning. Morphological descriptions and molecular characterization of two G. excentricus strains isolated from Brazil and maintained in culture were provided. The most complete description of the morphology of the sulcal region of Gambierdiscus based on light and scanning electron microscopy was presented. The sulcal area morphology and nomenclature used by different authors to name the sulcal plates in Gambierdiscus were reviewed. Two small sulcal plates (S.m.a. and S.m.p.) were shown for the first time. Phylogenetic trees based on D1-D3 and D8-D10 large subunits of ribosomal RNA gene sequences showed that the strains of G. excentricus from Brazil clustered with strains of G. excentricus isolated from its type locality, the Canary Islands. Both phylogenetic trees reconstructed the same relationships among all the formally described Gambierdiscus species and Gambierdiscus sp. ribotype 2 and Gambierdiscus sp. type 2. [ABSTRACT FROM AUTHOR]

The release of polycyclic aromatic hydrocarbons (PAHs) into the environment has increased very substantially over the last decades. PAHs are hydrophobic molecules which can accumulate in high concentrations in sediments acting then as major secondary sources. Fish contamination can occur through contact or residence nearby sediments or though dietary exposure. In this study, we analyzed certain physiological traits in unexposed fish (F1) issued from parents (F0) exposed through diet to three PAH mixtures at similar and environmentally relevant concentrations but differing in their compositions. For each mixture, no morphological differences were observed between concentrations. An increase in locomotor activity was observed in larvae issued from fish exposed to the highest concentration of a pyrolytic (PY) mixture. On the contrary, a decrease in locomotor activity was observed in larvae issued from heavy oil mixture (HO). In the case of the third mixture, light oil (LO), a reduction of the diurnal activity was observed during the setup of larval activity. Behavioral disruptions persisted in F1-PY juveniles and in their offspring (F2). Endocrine disruption was analyzed using cyp19a1b:GFP transgenic line and revealed disruptions in PY and LO offspring. Since no PAH metabolites were dosed in larvae, these findings suggest possible underlying mechanisms such as altered parental signaling molecule and/or hormone transferred in the gametes, eventually leading to early imprinting. Taken together, these results indicate that physiological disruptions are observed in offspring of fish exposed to PAH mixtures through diet. [ABSTRACT FROM AUTHOR]