Larval Red Drum (Sciaenops ocellatus) Sublethal Exposure to Weathered Deepwater Horizon Crude Oil: Developmental and Transcriptomic Consequences.

The Deepwater Horizon (DWH) incident resulted in extensive oiling of the pelagic zone and shoreline habitats of many commercially important fish species. Exposure to the water-accommodated fraction (WAF) of oil from the spill causes developmental toxicity through cardiac defects in pelagic fish species. However, few studies have evaluated the effects of the oil on near-shore estuarine fish species such as red drum (Sciaenops ocellatus). Following exposure to a certified weathered slick oil (4.74 µg/L ∑PAH50) from the DWH event, significant sublethal impacts were observed ranging from impaired nervous system development [average 17 and 22% reductions in brain and eye area at 48 h postfertilization (hpf), respectively] to abnormal cardiac morphology (100% incidence at 24, 48, and 72 hpf) in red drum larvae. Consistent with the phenotypic responses, significantly differentially expressed transcripts, enriched gene ontology, and altered functions and canonical pathways predicted adverse outcomes in nervous and cardiovascular systems, with more pronounced changes at later larval stages. Our study demonstrated that the WAF of weathered slick oil of DWH caused morphological abnormalities predicted by a suite of advanced bioinformatic tools in early developing red drum and also provided the basis for a better understanding of molecular mechanisms of crude oil toxicity in fish.

Congenital malformations and other reproductive losses in goats due to poisoning by Poincianella pyramidalis (Tul.) L.P. Queiroz (=Caesalpinia pyramidalis Tul.).

In the semiarid region of Brazil, in areas with vegetation composed mainly of Poincianella pyramidalis, several cases of congenital malformation and reproductive losses were observed in goats and sheep from 2012 to 2014. To determine the teratogenic effect of P. pyramidalis, two groups of eight goats each were used. Goats from Group 1 received fresh P. pyramidalis, harvested daily, as the only roughage during the whole breeding and pregnancy period. Goats in Group 2 (control) received Cynodon dactylon (tifton) hay free choice. Ultrasound examination for pregnancy diagnosis was performed every 28 days. Four goats from Group 1 were pregnant on day 28 but not on day 56, suggesting embryonic death or abortion. Another goat from Group 1 died at day 70 of pregnancy, and the fetuses exhibited micrognathia. The other three goats bore six kids, three of which showed bone malformations in the limbs, spine, ribs, sternum, and head, including arthrogryposis, scoliosis and micrognathia. One kid also showed hypoplasia of the left pulmonary lobes. In the control group, all goats bore a total of 13 kids and none of them exhibited malformations. These results demonstrated that P. pyramidalis causes congenital malformations and other reproductive losses in goats.

Biomedical applications of poisonous plant research.

Research designed to isolate and identify the bioactive compounds responsible for the toxicity of plants to livestock that graze them has been extremely successful. The knowledge gained has been used to design management techniques to prevent economic losses, predict potential outbreaks of poisoning, and treat affected animals. The availability of these compounds in pure form has now provided scientists with tools to develop animal models for human diseases, study modes of action at the molecular level, and apply such knowledge to the development of potential drug candidates for the treatment of a number of genetic and infectious conditions. These advances are illustrated by specific examples of biomedical applications of the toxins of Veratrum californicum (western false hellebore), Lupinus species (lupines), and Astragalus and Oxytropis species (locoweeds).

Female reproductive tract abnormalities in European hares (Lepus europaeus) in Australia. philip.stott@adelaide.edu.au.

Populations of European hare (Lepus europaeus) are in decline in Europe, and populations in Australia remain at low densities. Populations are sensitive to size of the breeding stock, which is influenced by fertility in the females. From 1996 to 1999, a total of 272 adult female hares from three Australian populations were dissected and their reproductive systems examined for abnormalities. Cystic endometrial hyperplasia was relatively common and often accompanied by hydrosalpinx. Extrauterine fetuses, neoplasms, pseudopregnancies, and resorptions also were found. However, although pseudopregnancies and resorptions were found in young adults (<12 mo) as well as older hares, conditions possibly causing infertility were almost always in older hares with prevalences up to 46.2%. Only hares with access to known sources of estrogens exhibited pathologic conditions, but sympatric European rabbits (Oryctolagus cuniculus) did not, which is consistent with known difference in responses between the corpora lutea of the two species to exogenous estrogen. Infertility at such a high prevalence could compound and extend the impact of years of low juvenile survival on recruitment.

Symptoms and implications of selenium toxicity in fish: the Belews Lake case example.

Belews Lake, North Carolina was contaminated by selenium in wastewater from a coal-fired power plant during the mid-1970s, and toxic impacts to the resident fish community (20 species) were studied for over two decades. Symptoms of chronic selenium poisoning in Belews Lake fish included, (1) telangiectasia (swelling) of gill lamellae; (2) elevated lymphocytes; (3) reduced hematocrit and hemoglobin (anemia); (4) corneal cataracts; (5) exopthalmus (popeye); (6) pathological alterations in liver, kidney, heart, and ovary (e.g. vacuolization of parenchymal hepatocytes, intracapillary proliferative glomerulonephritis, severe pericarditis and myocarditis, necrotic and ruptured mature egg follicles); (7) reproductive failure (reduced production of viable eggs due to ovarian pathology, and post-hatch mortality due to bioaccumulation of selenium in eggs); and (8) teratogenic deformities of the spine, head, mouth, and fins. Important principles of selenium cycling and toxicity were documented in the Belews Lake studies. Selenium poisoning in fish can be 'invisible', because, the primary point of impact is the egg, which receives selenium from the female's diet (whether consumed in organic or inorganic forms), and stores it until hatching, whereupon it is metabolized by the developing fish. If concentrations in eggs are great enough (about 10 microg/g or greater) biochemical functions may be disrupted, and teratogenic deformity and death may occur. Adult fish can survive and appear healthy despite the fact that extensive reproductive failure is occurring--19 of the 20 species in Belews Lake were eliminated as a result of this insidious mode of toxicity. Bioaccumulation in aquatic food chains causes otherwise harmless concentrations of selenium to reach toxic levels, and the selenium in contaminated sediments can be cycled into food chains for decades. The lessons learned from Belews Lake provide information useful for protecting aquatic ecosystems as new selenium issues emerge.

Field applications of the piscine anaphase aberration test: lessons from the Exxon Valdez oil spill.

Several large-scale genotoxicity assessments have been performed in coastal marine areas that have demonstrated either localized or widespread genetic effects resulting from human activity. One common assessment method is the anaphase aberration test, a measurement of abnormal chromosome division, using embryolarval fishes. It can be used to detect the presence of mutagens within a poorly characterized complex mixture or monitor specific genotoxins and is easily adapted for laboratory screening. One comprehensive marine genotoxicity assessment was conducted using Pacific herring (Clupea pallasi) following the Exxon Valdez oil spill (EVOS) in Prince William Sound (PWS), AK in late March 1989. In early May, genetic damage was detected at many sites within the oil trajectory and was correlated with concentrations of polycyclic aromatic hydrocarbons characteristic of Exxon Valdez oil (EVO) in intertidal mussels. Effects were related spatially and temporally to oil exposure. Anaphase aberration rates decreased throughout May and June 1989, and by 1991, genotoxicity was undetectable. The abundance of the 1989 herring year class in PWS is significantly reduced; this is the first reported example linking genotoxicity to subsequent population level effects. This review describes the methodology for the anaphase aberration test using fish eggs, its applications for large-scale assessments and supportive laboratory studies, and its limitations for prediction of higher level effects on populations.

A teratogenic deformity index for evaluating impacts of selenium on fish populations.

This paper describes a method for using teratogenic deformities in fish as the basis for evaluating impacts of selenium contamination. Teratogenic deformities are reliable bioindicators of selenium toxicosis in fish. They are produced in response to dietary exposure of parent fish and subsequent deposition of selenium in eggs. There is a close parallel between selenium concentrations in eggs, incidence of teratogenic deformities in larvae, and magnitude of reproductive failure. Using these relationships, an index was developed for teratogenic-based assessment of impacts to fish populations. The index is composed of three ratings that signify increasing levels of terata-induced population mortality: 1, negligible impact (< 5% population mortality); 2, slight to moderate impact (5-20% population mortality); 3, major impact (> 20% population mortality). Each rating is based on the anticipated population-level impact of the corresponding degree of mortality. Teratogenic-based impact assessment provides a conclusive cause-effect linkage between the contaminant and the fish. It is particularly useful for verifying selenium-induced impacts on reproductive success because poor reproduction can be caused by many things-i.e., fluctuating water levels, nest predation, food shortages, poor recruitment, etc. The index given here should be a useful tool for evaluating the effect of selenium on fish populations. Moreover, application of this technique may save considerable time and money by identifying the most efficient use of manpower and funds early in the assessment process.

Sterilisation of avian embryos with busulphan.

The chemosterilant drug busulphan (1, 4-butanediol dimethane sulphonate) has been applied to embryos of the domestic fowl at doses of from 1 to 500 micrograms after 48 hours incubation. Direct application caused a number of teratological effects. These could be avoided by injecting the drug in sesame oil directly into the yolk. Embryos treated in this way could be sterilised with an efficiency of over 95 per cent with minimal side effects to the young embryo. The technique provides a method for destroying primordial germ cells that will facilitate studies of germ cell/stroma interactions in the gonad and facilitate the production of transgenic birds.

Selenium toxicosis in wild aquatic birds.

Severe gross and microscopic lesions and other changes were found in adult aquatic birds and in embryos from Kesterson Reservoir (a portion of Kesterson National Wildlife Refuge), Merced County, Calif., during 1984. Adult birds from that area were emaciated, had subacute to extensive chronic hepatic lesions, and had excess fluid and fibrin in the peritoneal cavity. Biochemical changes in their livers included elevated glycogen and non-protein-bound sulfhydryl concentrations and glutathione peroxidase activity but lowered protein, total sulfhydryl, and protein-bound sulfhydryl concentrations. Congenital malformations observed grossly in embryos were often multiple and included anophthalmia, microphthalmia, abnormal beaks, amelia, micromelia, ectrodactyly, and hydrocephaly. Mean concentrations of selenium in livers (94.4 ppm, dry weight) and kidneys (96.6 ppm) of birds collected at the Kesterson ponds were about 10 times those found at a nearby control area (8.3 and 12.2 ppm). We conclude that selenium present in the agricultural drainage water supplied to the Kesterson ponds accumulated in the food chain of aquatic birds to toxic concentrations and caused the lesion and other changes observed.

Selenium accumulation in mammals exposed to contaminated California irrigation drainwater.

In May 1984, 332 mammals of 10 species were collected at Kesterson Reservoir (San Joaquin Valley, Merced Co., CA), which had received selenium-laden irrigation drainwater, and at the nearby Volta Wildlife Area, which had not. The study concentrated on the California vole (Microtus californicus); 88 were taken at Kesterson, 89 at Volta. Mean selenium concentrations in livers were as much as 522 times higher at Kesterson. There were species-to-species differences at Kesterson; higher selenium concentrations occurred in carnivorous species and/or species that feed on foods closely linked to pond water. There were also pond-to-pond differences at Kesterson; drainwater historically was delivered to Ponds 1 and 2, where concentrations in 1984 were higher, with subsequent flow to other ponds, where they were lower. Whereas none of 50 adult female voles from Kesterson was pregnant, 12 of 41 (29%) from Volta were pregnant. However, this cessation of reproductive activity at Kesterson was probably not due to selenium toxicity but could have resulted because drying conditions at Kesterson forced voles to a seed diet earlier than at Volta. One malformation was found among five embryonic litters of three species from Kesterson. Mammals seem much less susceptible to selenium-induced embryonic abnormalities than birds. No adverse impacts of selenium on wild mammals were demonstrated; however, some sensitive species might have been extirpated from Kesterson before this study began. In addition, high concentrations in small mammal species at Kesterson may threaten predatory birds and mammals that feed on them, with the endangered San Joaquin kit fox (Vulpes macrotis mutica) of particular concern.

A murine model for the assessment of placental and fetal development in teratogenicity studies.

During normal pregnancy in the mouse, maternal serum levels of the analogues to human schwangerschaftsprotein-1 and alpha-fetoprotein correlate significantly with the growth of the placenta and fetus respectively. This relationship has been utilized in the analysis of the effect of sodium selenite on placental and fetal growth in mice. Moderate doses of sodium selenite did not affect the growth of the placenta and fetus significantly, whereas high doses of selenite resulted in a large percentage of abortions. The protein markers were found to be useful in the prediction of placental and fetal growth, and they are suggested to be of general use in the study of the impact of teratogenic substances, since they reflect the status of the fetoplacental mass during gestation.

Safety of fenbendazole use in cattle.

Fenbendazole (Panacur: Hoechst) has a low degree of toxicity, teratogenicity and adverse effects on the reproductive tract, and a high degree of safety in experimental animals. Acute, subacute and long-term toxicity trials in cattle given fenbendazole at dosages of up to 2 g/kg revealed no adverse effects. Studies of teratogenicity, effects on fertility, compatibility with other drugs, and safety for animal handlers had similarly negative results.

Teratogens in plants.

Many compounds synthesized by plants are known to be teratogenic in laboratory animals, but only a few have been shown by feeding trials to produce terata in livestock. Studies of plant teratogens affecting livestock have not moved forward in a systematic nor rapid way because of the logistical problems connected with such experiments in large animals. Information that has accumulated can be conveniently separated into three categories: (1) known teratogens in known teratogenic plants, (2) known teratogenic plants with unidentified teratogens, and (3) suspected teratogenic plants. Included in the first group are the teratogens from Lupinus, Veratrum, Conium and Leucaena genera; in the second group are included the Astragalus , Nicotiana and Trachymene genera; and in the third group are included Datura, Prunus , Sorghum and Senecio genera. Total available information in each case varies, but in a few instances considerable fundamental as well as practical information is now known. Research has provided enough information in a few instances to enable elimination of the practical problem or significant reduction in incidence.

Albendazole : a comparison of relay embryotoxicity with embryotoxicity of individual metabolites.

By using an experimental model compound (Albendazole, an anthelmintic) the authors compared two methodologies for the toxicological evaluation of bovine hepatic residues. Toxicity was not demonstrated for bovine hepatic residues in a relay embryotoxicity study in the rat. On the other hand, both albendazole and its sulfoxide metabolite produce embryotoxic effects in this rat model. These different results are discussed and explained by considerations related to the no effect levels and the chemical nature of the different types of residues.

Public health hazards from electricity-producing plants.

When a new electricity-producing plant is to be built in a given locality it is natural to take into account the public health consequences of the normal operation of each type of plant contemplated. Here, the fossil-burning plants and nuclear facilities come under consideration. I have attempted to show that, in spite of the many important studies performed, there is currently no reliable methodology to estimate how many more cancer cases, and how many more heart attacks and other diseases have to be anticipated as a consequence of the normal operation of this or that type of electric generator. In part, this is because the currently available estimates of radiation effects on humans are based on extrapolations from studies of two kinds. Those of one kind may be exemplified by studies of atomic bomb casualties in Hiroshima and Nagasaki. The other kind are laboratory experiments with lower animals, frequently mice. The unreliability of both kinds of extrapolations is connected with the following circumstances: (i) The omnipresent troublesome phenomenon of competing risks. (ii) The dependence of health effects of a given noxious agent on the preexisting local pollution. (iii) The dependence of health effects not only on the "dose" of an agent, but also on the rate at which the agent is administered. (iv) The noted difficulties of making extrapolations from one mammal to another. Our obtaining reliable estimates of the public health effects of extra pollution from new industrial plants would seem to depend on a large multipollutant and multilocality epidemiological study being conducted--one requiring the cooperative effort of several governmental agencies. However, a much easier study of certain developments in the vicinity of Rocky Flats, Colorado, might provide important direct information on health phenomena as they occur in real life.

A mutual protective effect of mercury and selenium in Japanese quail.

Dietary interactions between methylmercury (Ch3Hg) and sodium selenite (Na2SeO3) were studied in Japanese quail. Addition of 0.35-6 p.p.m. Se to diets containing toxic levels of Hg (5-30 p.p.m. Hg) reduced the toxicity of methylmercury and increased the survival of Japanese quail. The survival increased with increasing levels of Se in the diet. Selenium as 6 p.p.m. did not cause any mortality in males and caused only relatively low mortality in females. However, 12 p.p.m. Se depressed the survival of quail, especially females. No consistent effect of Hg, Se or both was observed on body weight or feed consumption. High levels of Hg reduced egg production, fertility and hatchability, and the addition of Se lessened these effects of Hg. Selenium in the diet alone (6 or 12 p.p.m.) generally produced lower hatchability and a high percentage of deformed embryos, and 12 p.p.m. Se also depressed egg production. Addition of 5-15 p.p.m. Hg to such Se diets overcame these effects and reduced the percentage of abnormal embryos more than 50%. Analysis of tissues for total Hg showed that Hg was distributed in a pattern typical for alkyl mercurials. Hg levels in Se-protected birds equaled or exceeded the levels in those fed Hg without Se. Se levels in tissues were generally elevated by feeding Hg, especially in brain. Extremely high brain Hg levels, up to 58 p.p.m., were observed in birds fed 15 p.p.m. Hg plus 6 p.p.m. Se for 20 weeks prior to sacrifice. The levels of Se in the brain of these birds was elevated (4 p.p.m.), but not equimolar to Hg.