Differential effects of high and low strength magnetic fields on mouse embryonic development and vasculogenesis of embryonic stem cells

Man-made magnetic fields (MFs) may exert adverse effects on mammalian embryonic development. Herein, we analysed the effect of 10 mT 50 Hz sinusoidal (AC) or static (DC) MFs versus 1 mT MFs on embryonic development of mice. Exposure for 20 days during gestation to 10 mT MFs increased resorptions and dead fetuses, decreased crown-rump length and fresh weight, reduced blood vessel differentiation and caused histological changes, accompanied with diminished vascular endothelial growth factor (VEGF) protein expression in several organs. In embryonic stem (ES) cell-derived embryoid bodies exposure towards 10 mT MFs increased reactive oxygen species (ROS), decreased vascular marker as well as VEGF expression and enhanced apoptosis. In conclusion, our combined data from in vivo and in vitro experiments identified VEGF as an important mediator during embryonic development that can be influenced by high strength MFs, which in consequence leads to severe abnormalities in fetus organs and blood vessel formation.     

In vivo studies on toxin accumulation in liver and ultrastructural changes of hepatocytes of the phytoplanktivorous bighead carp i.p.-injected with extracted microcystins.

Phytoplanktivorous bighead carp were injected i.p. with extracted microcystins (mainly MC-RR and -LR) at two doses, 200 and 500 MC-LReq.microg kg(-1) bw, and the changes in extractable MCs in liver and in the ultrastructure of hepatocytes were studied at 1, 3, 12, 24 and 48 h after injection. Quantitative and qualitative determinations of MCs in the liver were conducted by HPLC and LC-MS, respectively. MC concentration in the liver reached the maxima at 12h (2.89 microg MCsg(-1) dry weight at the lower dose) or at 3h (5.43 microg MCsg(-1) dry weight at the higher dose) post-injection, followed by sharp declines afterwards, whereas the ultrastructural changes of hepatocytes in both dose groups suggest progressive increases in severity toward the directions of apoptosis and necrosis from 1 to 24h, respectively. There were two new findings in fish: widening of intercellular spaces was among the early ultrastructural changes induced by MCs and ultrastructural recovery of hepatocytes was evident at 48 h post-injection in both dose groups. Both the present and previous studies suggest that with in vivo or in vitro exposure to microcystins, hepatocyte damage in fish tends to proceed toward the direction of apoptosis at lower MC concentrations but toward the direction of necrosis at high MC concentrations. The temporal dynamics of MCs in the liver suggest that bighead carp may have a mechanism to degrade or bind MC-LR actively after it enters the blood system.     

The effects of elutriates from PAH and heavy metal polluted sediments on Crassostrea gigas (Thunberg) embryogenesis,larval growth and bio-accumulation by the larvae of pollutants from sedimentary origin

The release, bio-availability and toxicity of contaminants, when sediments are resuspended have been examined, studying concurrently their effects on the embryogenesis and on the larval growth of the Crassostrea gigas larvae and their bio-accumulation in those organisms. Three characteristic sediments have been selected (one contaminated by PAHs, a second by heavy metals and the last by the both pollutants). The organisms were directly exposed to elutriates obtained from each sediment or fed on algae (Isochrysis galbana) contaminated with the same elutriates. The elutriates used in this study show contamination levels similar to those observed in some polluted coastal and estuary environments. The larval growth test has appeared to be more sensitive that the embryotoxicity test. The biological effects and the contaminant bio-accumulation were more pronounced when larvae were directly exposed to different elutriates. In the case of PAHs, the contamination of algae was sufficient to lead to effect on the larval growth of the Crassostrea gigas. In all cases, a fraction of contaminants adsorbed on suspended particles was bio-available and accumulated by the larvae. This study has shown that resuspending polluted sediments constitutes a threat to pelagic organisms and than the C. gigas larval growth may be proposed as a test to protect the most sensitive areas.     

Effects of acetaminophen (paracetamol) in the embryonic development of zebrafish,Danio rerio

Acetaminophen, or paracetamol is an over‐the‐counter analgesic generally used by all groups of people, including pregnant women. The present investigation aims to elucidate the effects of acetaminophen on the development of zebrafish Danio rerio in which embryogenesis is ex utero. Developing eggs (n = 30) were exposed to different doses (0, 1, 5, 10, 50 and 100 µg L^?1) of the drug in triplicate and observations were made hourly until gastrulation and once in 24 h thereafter for seven consecutive days. Acetaminophen induced anomalies at different levels of development in a dose‐dependent manner, causing impairment in (1) the early development, (2) hatching, (3) organogenesis (by altering the rate of apoptosis), (4) larval growth and morphometry, (5) tail and tail‐fin formation, (6) pigmentation and (7) larval behavior and survival. The results of the present study clearly reveal that acetaminophen interfered with the normal embryonic development, growth, behavior and survival of D. rerio larvae. Copyright © 2009 John Wiley & Sons, Ltd.     

Chronic effects of strobilurin fungicides on development,growth, and mortality of larval Great Plains toads (Bufo cognatus)

Agricultural fungicide application has increased tenfold since 2005 in the United States. Active ingredients and formulations of strobilurin fungicides at environmentally relevant concentrations cause mortality to larval and metamorph amphibians; however, little is known about chronic exposure effects in amphibians. We exposed larval amphibians (Bufo cognatus) throughout metamorphosis to the common fungicide formulations Headline^®, Stratego^®, Quilt^®, and a control to determine effects on development and growth. Formulations were tested at 1.7, 50, and 400 μg/L of the active strobilurin ingredient for Headline^®, Stratego^®, and Quilt^®, respectively. Fungicide exposure did not affect body mass or snout–vent length at metamorphosis. However, exposure to Headline^® at 1.7 μg/L increased the development rate of tadpoles by approximately 5 days compared to the control, an effect not observed for Stratego^® and Quilt^®. Stratego^® also caused approximately 35 % cumulative mortality. Results from the experiment suggest that chronic effects of strobilurin fungicides on development, growth, and mortality to B. cognatus are apparent at environmentally relevant concentrations.     

Effects of microcystins on the growth and the activity of superoxide dismutase and peroxidase of rape (Brassica napus L.) and rice (Oryza sativa L.).

Microcystins are naturally occurring hepatotoxic cyclic heptapeptides produced by some toxic freshwater cyanobacterial species. In this study, crude extract of toxic cyanobacterial blooms from Dianchi Lake in southwestern China was used to determine the effects of microcystins on rape (Brassica napus L.) and rice (Oryza sativa L.). Experiments were carried out on a range of doses of the extract (equivalent to 0, 0.024, 0.12, 0.6 and 3 microg MC-LR/ml). Investigations showed that exposure to microcystins inhibited the growth and development of both rice and rape seedlings, however, microcystins had more powerful inhibition effect on rape than rice in germination percentage of seeds and seedling height. Microcystins significantly inhibited the elongation of primary roots of rape and rice seedlings. Determination of the activities of peroxidase and superoxide dismutase demonstrated that microcystin stress was manifested as an oxidative stress. Using ELISA, microcystins were examined from the extract of exposed rape and rice seedlings, indicating that consumption of edible plants exposed to microcystins via irrigation route may have health risks. Significantly different levels of recovered microcystins between exposed rice and rape seedlings suggested that there might be different tolerant mechanisms toward microcystins.     

Effects of fenvalerate on larval development of Palaemonetes pugio (holthuis) and on larval metabolism during osmotic stress

Larvae of the estuarine grass shrimp, Palaemonetes pugio, were reared in the laboratory from hatch through metamorphosis under optimal salinity conditions (20‰) in a range of lethal and sublethal concentrations of the pyrethroid insecticide, fenvalerate. A nominal concentration of 3.2 ng fenvalerate/l significantly reduced the percentage of larvae that completed metamorphosis. Oxygen consumption rates were significantly higher for larvae exposed to this lethal concentration for only 24 h. Exposure to a sublethal concentration of 1.6 ng fenvalerate/l prolonged the duration of complete larval development.Acute osmotic stress modified the metabolism of larval P. pugio reared in sublethal fenvalerate concentrations of 0.1 and 0.2 ng/l and these metabolic responses varied with stage of development. After 8 days of exposure to fenvalerate, oxygen consumption rates were elevated when larvae were exposed acutely to hypoosmotic stress (10‰ S). Metabolic responses of premetamorphic larvae to hypersomotic stress (30‰ S) were also modified by sublethal fenvalerate exposure. Alterations in metabolic-salinity patterns of larval grass shrimp developing under sublethal concentrations of fenvalerate suggest reduction in the ecological fitness of this sensitive life stage by limiting their capacity to adapt to the fluctuating salinity conditions of estuarine waters.     

1,2-Dibromo-4-(1,2-dibromoethyl)-cyclohexane and tris(methylphenyl) phosphate cause significant effects on development,mRNA expression,and circulating bile acid concentrations in chicken embryos

1,2-Dibromo-4-(1,2-dibromoethyl)-cyclohexane (DBE-DBCH; formerly abbreviated as TBECH) and tris(methylphenyl) phosphate (TMPP; formerly abbreviated as TCP) are additive flame retardants that are detected in the environment and biota. A recent avian in vitro screening study of 16 flame retardants identified DBE-DBCH and TMPP as important chemicals for follow-up in ovo evaluation based on their effects on cytotoxicity and mRNA expression in avian hepatocytes. In this study, technical mixtures of DBE-DBCH and TMPP were injected into the air cell of chicken embryos at concentrations ranging from 0 to 54,900 ng/g and from 0 to 261,400 ng/g, respectively, to determine effects on pipping success, development, hepatic mRNA expression, thyroid hormone levels, and circulating bile acid concentrations. Both compounds were detectable in embryos at pipping and the β-DBE-DBCH isomer was depleted more rapidly than the α-isomer in tissue samples. DBE-DBCH had limited effects on the endpoints measured, with the exception of the up-regulation of two phase I metabolizing enzymes, CYP3A37 and CYP2H1. TMPP exposure caused embryonic deformities, altered growth, increased liver somatic index (LSI) and plasma bile acid concentrations, and altered mRNA expression levels of genes associated with xenobiotic and lipid metabolism and the thyroid hormone pathway. Overall, TMPP elicited more adverse molecular and phenotypic effects than DBE-DBCH albeit at concentrations several orders of magnitude greater than those detected in the environment. The increase in plasma bile acid concentrations was a useful phenotypic anchor as it was associated with a concomitant increase in LSI, discoloration of the liver tissue, and modulation of hepatic genes involved with xenobiotic and lipid metabolism.     

Interactive effects of cadmium and Microcystis aeruginosa (cyanobacterium) on the growth,antioxidative responses and accumulation of cadmium and microcystins in rice seedlings

Ecotoxicology - Cadmium pollution and harmful cyanobacterial blooms are two prominent environmental problems. The interactive effects of cadmium(II) and harmful cyanobacteria on rice seedlings...     

Histopathological and genotoxic effects of pollution on Nile Tilapia (Oreochromis niloticus,Linnaeus, 1758) in the Billings Reservoir (Brazil)

The Billings Reservoir shows eutrophic waters due to the large amount of sewage, and consequently, the fish can be a problem for public health. Thus, this project aimed to analyze the histological gills and liver of Nile tilapia to verify morphological changes caused by environment, and the frequency of micronuclei was done, to observe the response to genotoxic activity. We observed histological alterations in gills and livers of Nile Tilapia classified as mild to severe, and the presence of micronucleus. The results enable better environmental monitoring and quality control of this species.     

The effects of tetrathiomolybdate (TTM, NSC-714598) and copper supplementation on fertility and early embryonic development in rats

Based on its ability to chelate copper, TTM is being studied as an antiangiogenic agent for cancer therapy. The purpose of this study was to evaluate the toxicity of TTM and the protection of copper supplementation on the reproductive capability of male and female CD rats. Doses of 0, 1, 4, and 12 mg/kg/day with copper supplementation (110 mg/kg of diet) were given by gavage. There were no effects on the estrous cycle or reproductive indices, or maternal toxicity in any female dose group. Male rats given 12 mg/kg/day showed significant decreases in body weight gains and food consumption, and anemia. Serum ceruloplasmin levels were dose-dependently decreased in all male dose groups. Reduced epididymal weights, sperm counts, and sperm motility, sperm morphologic abnormalities and histopathologic changes in testis and epididymis occurred only at 12 mg/kg/day. Dietary copper supplementation prevented the adverse sperm effects produced by 12 mg/kg/day of TTM.     

The histopathological,cytopathological and ultrastructural effects of carbaryl on gills of Oreochromis niloticus (Linnaeus, 1758)

Ultrastructural and histopathological reponses in the organs of living organisms are important and useful tools to determine the health condition and the effects of pollutants, such as pesticides, on the organisms. The aim of this study is to determine possible histopathological, cytopathological and ultrastructural alterations in gills of Oreochromis niloticus individuals exposed to 850 μg/L carbaryl standart at 7th, 14th and 21st days with light and electron microscopes. The fish were exposed to carbaryl for 21 days and the histopatological, ultrastructural and cytopathological alterations occuring in the gill tissues of organisms were determined by light, Scanning and Transmission Electron Microscopes (SEM and TEM). At the end of the study, it was observed that carbaryl caused both histopathological and cytopathological changes in the gills of O. niloticus. It has been determined that the most of the pathological changes in the exposed organisms are the metabolic defence reactions.     

The effects of additives on the growth and morphology of paracetamol (acetaminophen) crystals

It is well known that the presence of impurities can dramatically affect the nucleation, morphology, and chemical properties of crystals. Although literature is replete with examples of impurity or additive-induced modifications of crystals, few have examined the interaction of these compounds with distinct growing faces. In this study, we utilize atomic force microscopy (AFM) and scanning electron microscopy (SEM) to investigate the influence of two structurally related additives of paracetamol (acetaminophen) on its crystal morphology. We also probe, in situ, the effects of these additives on the morphology and growth rate of steps on the (0 0 1) face of the crystal. This study, in conjunction with further investigations, aims to establish the specific mechanisms of inhibition of these additives on each face of paracetamol, and provide a means of overcoming the poor compaction behaviour of paracetamol.     

The combined and separate effects of copper and cadmium on the growth of Campanularia flexuosa (hydrozoa) colonies

The growth of Campanularia flexuosa has been studied in experiments in which cultured colonies have been exposed to copper and cadmium, separately and in various combinations of concentrations. The results of different experiments have been used to construct a response surface and to show how it develops with time. The data suggest that while the effect of mixtures of copper and cadmium are more or less additive over much of the response surface, where growth is inhibited most, both antagonistic and synergistic effects may occur.     

Toxicity of organic selenium (Selemax) and its effects on haematological and biochemical parameters and histopathological changes of common carp (Cyprinus carpio L., 1758)

The aim of this study was to assess the effect of organic selenium (Selemax) on Common carp (Cyprinus carpio). The effect was determined on basis of acute toxicity, haematological, biochemical profile and histopathology. A static toxicity test was performed for the determination of 96?h median lethal concentration. The 96hLC50 value of Selemax was 0.54?mg/L. For investigation of chronic toxicity, the experimental group exposed to Selemax in concentration 0.054?mg/L (10% 96hLC50) during 28 days showed significant changes in haematological and biochemical profile and caused histopathological changes in liver, and kidney. According to those data, it was possible to classify organic selenium as highly toxic for carp. The alterations of these parameters can be used as suitable biomarkers in monitoring of organic selenium in the aquatic environment.     

Phenobarbitone: adverse effects on reproductive performance and offspring development in the Mongolian gerbil, (Meriones unguiculatus)

Phenobarbitone at a concentration of 500 mg/l in drinking fluid of gerbils during pregnancy (60 mg/kg) and lactation (136 mg/kg) markedly reduced the proportion of animals bearing litters, decreased pup weights at birth and during later life and delayed development of the self-righting reflex, auditory startle reaction, eye opening and full fur coverage. It also prolonged the period of suckling. Scars of implantation were evident in uterine horns of 60% of treated and in none of control females that had failed to give birth. Treated offspring after weaning were given phenobarbitone (500 mg/l; 42–124 mg/kg) as their drinking fluid throughout life and a further group of gerbils received this concentration of the drug from the time of weaning. Seizure susceptibility was unaltered by the drug treatment, and the only evidence of behavioural change was seen in offspring gerbils at 6 weeks when the bout length of social investigation during encounters was increased. Drug-treated offspring showed no abnormality in brain weight relative to body weight. Weight gain and brain weight remained normal among the gerbils given phenobarbitone after weaning. The drug treatment reduced scent gland size in breeding males, though not in the offspring, and had no effect on weights of the testes or ovaries and uterus. Plasma concentrations of phenobarbitone in females of the postweaning group amounted on average to 4.4 mg/kg. Most of the adverse effects of this dose of phenobarbitone in the gerbil can thus be seen to be associated either with reproductive impairment or with exposure during sensitive periods of early development.     

维生素A缺乏及补充对小鼠子代发育的影响

目的通过建立小鼠维生素A缺乏模型,研究维生素A对小鼠胎仔发育的影响。方法对维生素A缺乏之孕鼠分不同阶段补充维生素A,观察胎鼠发育情况。结果维生素A缺乏使胎鼠的体重、身长、尾长明显小于正常对照组(P＜0.05),囟门矢义冠内0.268cm×0.228cm,明显大于对照组的0.206cm×0.078cm;骨异常率为33.33％,对照组仅为7.32％,胸骨异常率为48.72％,对照组为2.44％,差异均有显著性明显大于正常对照组,胎仔骨骼发育异常,神经反射发育迟缓,且出现脑膨出及细小肾等畸形。交配后第7天补充组明显好于缺乏组,但与正常对照组相比仍有差异。交配后第0天补充组与正常对照组无差异。结论揭示维生素A对胚胎的生长发育十分重要。     

Molecular and cellular effects of chemicals disrupting steroidogenesis during early ovarian development of brown trout (Salmo trutta fario)

A range of chemicals found in the aquatic environment have the potential to influence endocrine function and affect sexual development by mimicking or antagonizing the effects of hormones, or by altering the synthesis and metabolism of hormones. The aim of this study was to evaluate whether the effects of chemicals interfering with sex hormone synthesis may affect the regulation of early ovarian development via the modulation of sex steroid and insulin‐like growth factor (IGF) systems. To this end, ex vivo ovary cultures of juvenile brown trout (Salmo trutta fario) were exposed for 2 days to either 1,4,6‐androstatriene‐3,17‐dione (ATD, a specific aromatase inhibitor), prochloraz (an imidazole fungicide), or tributyltin (TBT, a persistent organic pollutant). Further, juvenile female brown trout were exposed in vivo for 2 days to prochloraz or TBT. The ex vivo and in vivo ovarian gene expression of the aromatase (CYP19), responsible for estrogen production, and of IGF1 and 2 were compared. Moreover, 17β‐estradiol (E2) and testosterone (T) production from ex vivo ovary cultures was assessed. Ex vivo exposure to ATD inhibited ovarian E2 synthesis, while T levels accumulated. However, ATD did not affect ex vivo expression of cyp19, igf1, or igf2. Ex vivo exposure to prochloraz inhibited ovarian E2 production, but did not affect T levels. Further prochloraz up‐regulated igf1 expression in both ex vivo and in vivo exposures. TBT exposure did not modify ex vivo synthesis of either E2 or T. However, in vivo exposure to TBT down‐regulated igf2 expression. The results indicate that ovarian inhibition of E2 production in juvenile brown trout might not directly affect cyp19 and igf gene expression. Thus, we suggest that the test chemicals may interfere with both sex steroid and IGF systems in an independent manner, and based on published literature, potentially lead to endocrine dysfunction and altered sexual development. © 2011 Wiley Periodicals, Inc. Environ Toxicol 29: 199–206, 2014.     

Toxic effects of indoxacarb enantiomers on the embryonic development and induction of apoptosis in zebrafish larvae (Danio rerio)

Indoxacarb is a highly potent insecticide widely used to control Lepidoptera insects in vegetable, tea, cotton, and rice fields. It can run off into aquatic environments. It is consisted of two enantiomers. Environmental risks and aquatic toxicity of indoxacarb enantiomers have not been fully investigated. In this study, zebrafish (Danio rerio ) embryos were exposed to varying concentrations of (?)‐R‐indoxacarb and (+)‐S‐indoxacarb until 96‐h post‐fertilization (hpf) to assess the embryonic toxicity. (?)‐R‐indoxacarb was 1.3‐fold more toxic than (+)‐S‐isomer to zebrafish embryos at 96 hpf. (?)‐R‐indoxacarb exhibited reduction in body length and pericardial edema compared with (+)‐S‐indoxacarb. (?)‐R‐indoxacarb decreased the hatching rate sixfold greater than (+)‐S‐indoxacarb. The rate of pericardial edema induced by (?)‐R‐indoxacarb was 2.5 times greater than that by (+)‐S‐indoxacarb. The heart rate of the larvae exposed to (?)‐R‐indoxacarb was 30% lower than that to (+)‐S‐indoxacarb. In addition, exposure to the chiral isomers resulted in significant increases in apoptosis; interestingly (?)‐R‐indoxacarb induced apoptosis in the heart area, whereas (+)‐S‐indoxacarb induced apoptosis in the head area. © 2015 Wiley Periodicals, Inc. Environ Toxicol 32: 7–16, 2017.