A comparative study on the embryonic development of gynogen, triploid, haploid and normal diploid embryos of stinging catfish, Heteropneustes fossilis

UV irradiation and cold shock were applied on the eggs of stinging catfish, Heteropneustes fossilis, to produce haploid,. gynogen and triploid embryos. A comparative account of the various features· of embryonic development in chromosomally manipulated groups viz. haploid, gynogen and triploid and non-manipulated normal diploid group of H fossilis has been discussed. A slow development and delayed hatching were observed in gynogen and triploid embryos compared to those in normal diploid (control) groups. Mass mortality was observed in all chromosomally manipulated groups particularly during the gastrulation stage. The hatchlings of the gynogen, triploid and normal diploid were similar in overall appearance.

The ontogeny of haematopoiesis in the marine teleost Leiostomus xanthurus and a comparison of the site of initial haematopoiesis with Opsanus tau

The ontogeny of haematopoiesis in the perciform fish, spot Leiostomus xanthurus, differed from that reported as the norm for fishes, as exemplified by the cypriniform zebrafish Danio rerio, and observed in the batrachoidiform oyster toadfish Opsanus tau. Erythropoiesis in spot was first evident in the head kidney of yolk-sac larvae 3 days after hatching (DAH). No embryonic intermediate cell mass (ICM) of primitive stem cells or blood islands on the yolk were apparent within embryos. Erythrocytes were first evident in circulation near the completion of yolk absorption, c. 5 DAH, when larvae were c. 20 mm notochord length (LN). Erythrocyte abundance increased rapidly with larval development for c. 14 to 16 DAH, then became highly variable following changes in cardiac chamber morphology and volume. Erythrocytic haemoglobin (Hb) was not detected within whole larvae until they were 12 DAH or c. 31 mm LN, well after yolk and oil-globule absorption. The Hb was not quantified until larvae were >47 DAH or >7 mm standard length. The delayed appearance of erythrocytes and Hb in spot was similar to that reported for other marine fishes with small embryos and larvae. In oyster toadfish, a marine teleost that exhibits large embryos and larvae, the ICM and Hb were first evident in two bilateral slips of erythropoietic tissue in the embryos, c. 5 days after fertilization. Soon thereafter, erythrocytes were evident in the heart, and peripheral and vitelline circulation. Initial haematopoiesis in oyster toadfish conformed with that described for zebrafish. While the genes that code for the development of haematopoiesis are conserved among vertebrates, gene expression lacks phylogenetic pattern among fishes and appears to conform more closely with phenotypic expression related to physiological and ecological influences of overall body size and environmental oxygen availability.

Magnitude and extent of chemical contamination and toxicity in sediments of Biscayne Bay and vicinity

The toxicity of sediments in Biscayne Bay and many adjoining tributaries was determined as part of a bioeffects assessments program managed by NOAA’s National Status and Trends Program. The objectives of the survey were to determine: (1) the incidence and degree of toxicity of sediments throughout the study area; (2) the spatial patterns (or gradients) in chemical contamination and toxicity, if any, throughout the study area; (3) the spatial extent of chemical contamination and toxicity; and (4) the statistical relationships between measures of toxicity and concentrations of chemicals in the sediments. The survey was designed to characterize sediment quality throughout the greater Biscayne Bay area. Surficial sediment samples were collected during 1995 and 1996 from 226 randomly-chosen locations throughout nine major regions. Laboratory toxicity tests were performed as indicators of potential ecotoxicological effects in sediments. A battery of tests was performed to generate information from different phases (components) of the sediments. Tests were selected to represent a range in toxicological endpoints from acute to chronic sublethal responses. Toxicological tests were conducted to measure: reduced survival of adult amphipods exposed to solid-phase sediments; impaired fertilization success and abnormal morphological development in gametes and embryos, respectively, of sea urchins exposed to pore waters; reduced metabolic activity of a marine bioluminescent bacteria exposed to organic solvent extracts; induction of a cytochrome P-450 reporter gene system in exposures to solvent extracts; and reduced reproductive success in marine copepods exposed to solid-phase sediments. Contamination and toxicity were most severe in several peripheral canals and tributaries, including the lower Miami River, adjoining the main axis of the bay. In the open basins of the bay, chemical concentrations and toxicity generally were higher in areas north of the Rickenbacker Causeway than south of it. Sediments from the main basins of the bay generally were less toxic than those from the adjoining tributaries and canals. The different toxicity tests, however, indicated differences in severity, incidence, spatial patterns, and spatial extent in toxicity. The most sensitive test among those performed on all samples, a bioassay of normal morphological development of sea urchin embryos, indicated toxicity was pervasive throughout the entire study area. The least sensitive test, an acute bioassay performed with a benthic amphipod, indicated toxicity was restricted to a very small percentage of the area. Both the degree and spatial extent of chemical contamination and toxicity in this study area were similar to or less severe than those observed in many other areas in the U.S. The spatial extent of toxicity in all four tests performed throughout the bay were comparable to the “national averages” calculated by NOAA from previous surveys conducted in a similar manner. Several trace metals occurred in concentrations in excess of those expected in reference sediments. Mixtures of substances, including pesticides, petroleum constituents, trace metals, and ammonia, were associated statistically with the measures of toxicity. Substances most elevated in concentration relative to numerical guidelines and associated with toxicity included polychlorinated biphenyls, DDT pesticides, polynuclear aromatic hydrocarbons, hexachloro cyclohexanes, lead, and mercury. These (and other) substances occurred in concentrations greater than effects-based guidelines in the samples that were most toxic in one or more of the tests. (PDF contains 180 pages)

Survey of sediment quality in Sabine Lake, Texas and vicinity

The toxicity of sediments in Sabine Lake, Texas, and adjoining Intracoastal Waterway canals was determined as part of bioeffects assessment studies managed by NOAA’s National Status and Trends Program. The objectives of the survey were to determine: (1) the incidence and degree of toxicity of sediments throughout the study area; (2) the spatial patterns (or gradients) in chemical contamination and toxicity, if any, throughout the study area; (3) the spatial extent of chemical contamination and toxicity; and (4) the statistical relationships between measures of toxicity and concentrations of chemicals in the sediments. Surficial sediment samples were collected during August, 1995 from 66 randomly-chosen locations. Laboratory toxicity tests were performed as indicators of potential ecotoxicological effects in sediments. A battery of tests was performed to generate information from different phases (components) of the sediments. Tests were selected to represent a range in toxicological endpoints from acute to chronic sublethal responses. Toxicological tests were conducted to measure: reduced survival of adult amphipods exposed to solid-phase sediments; impaired fertilization success and abnormal morphological development in gametes and embryos, respectively, of sea urchins exposed to pore waters; reduced metabolic activity of a marine bioluminescent bacteria exposed to organic solvent extracts; and induction of a cytochrome P-450 reporter gene system in exposures to solvent extracts of the sediments. Chemical analyses were performed on portions of each sample to quantify the concentrations of trace metals, polynuclear aromatic hydrocarbons, and chlorinated organic compounds. Correlation analyses were conducted to determine the relationships between measures of toxicity and concentrations of potentially toxic substances in the samples. Based upon the compilation of results from chemical analyses and toxicity tests, the quality of sediments in Sabine Lake and vicinity did not appear to be severely degraded. Chemical concentrations rarely exceeded effects-based numerical guidelines, suggesting that toxicant-induced effects would not be expected in most areas. None of the samples was highly toxic in acute amphipod survival tests and a minority (23%) of samples were highly toxic in sublethal urchin fertilization tests. Although toxic responses occurred frequently (94% of samples) in urchin embryo development tests performed with 100% pore waters, toxicity diminished markedly in tests done with diluted pore waters. Microbial bioluminescent activity was not reduced to a great degree (no EC50 <0.06 mg/ml) and cytochrome P-450 activity was not highly induced (6 samples exceeded 37.1 ug/g benzo[a]pyrene equivalents) in tests done with organic solvent extracts. Urchin embryological development was highly correlated with concentrations of ammonia and many trace metals. Cytochrome P450 induction was highly correlated with concentrations of a number of classes of organic compounds (including the polynuclear aromatic hydrocarbons and chlorinated compounds). (PDF contains 51 pages)

Sexual Reproduction and Early Development in the Estuarine Sea Anemone, Nematostella vectensis Stephenson, 1935

This dissertation: 1) determines the factor(s) responsible for spawning induction in NematosteJla vectensis; 2) isolates, describes, and documents the source of jelly from egg masses of N. vectensis; and 3) describes N. vectensis' early development. Namatostella vectensis were maintained on a 7-day mussel feeding/water change regime over 159 days. Within 36 hours of mussel feeding/water change. 69.1% of females and 78.5% of males spawned reliably. Through manipulation of feeding, water change, oxygen and nitrogenous waste concentrations, spawning induction was found to be triggered by the oxygen concentration associated with water change, and not by feeding. Ammonia, anemones' major waste product, inhibited this induction in a concentration-dependent manner. Female N. vectensis release eggs in a persistent jellied egg mass which is unique among the Actiniaria. The major component of this egg mass jelly was a positive periodic acid-Schiffs staining, 39.5-40.5 kD glycoprotein. Antibodies developed in rabbits against this glycoprotein bound to jelly of intact egg masses and to granules (~ 2.8 IJm in diameter) present in female anemone mesenteries and their associated filaments. Antibodies did not label male tissues. Nematostella vecfensis embryos underwent first karyokinesis -60 minutes following the addition of sperm to eggs. Second nuclear division took place, followed by first cleavage, 90-120 minutes later. Each of the 4 blastomeres that resulted from first cleavage contained a single nucleus. Arrangement of these blastomeres ranged from radial to pseudospiral. Embryonic development was both asynchronous and holoblastic. Following formation of the 4-cell stage, 71% of embryos proceeded to cleave again to form an 8-cell stage. In each of the remaining 29% of embryos, a fusion of from 2-4 blastomeres resulted in 4 possible patterns which had no affect on either cleavage interval timing or subsequent development. The fusion event was not due to ooplasmic segregation. Blastomeres isolated from 4-celled embryos were regulative and developed into normal planula larvae and juvenile anemones that were 1/4 the size of those that developed from intact 4-celled embryos. Embryos exhibiting the fusion phenomenon were examined at the fine structural level. The fusion phenomenon resulted in formation of a secondary syncytium and was not a mere compaction of blastomeres.

Marine Ranching: Proceedings of the Eighteenth U.S.-Japan Meeting on Aquaculture Port Ludlow, Washington, 18-19 September 1989

Female reproduction in penaeid shrimp is carefully regulated by several different endocrine factors. Their precise modes of action have not yet been fully elucidated. Three endocrine factors, each representing a different chemical class of hormones, have been investigated in the penaeid shrimp Sicyonia ingentis in our laboratory: ecdysteroids, vitellogenesis-inhibiting hormone (VIH) , and methyl farnesoate (MF). Ecdysteroids (the steroid molting hormones of arthropods; predominantly 20-hydroxyecdysone), are initially present in low levels (<10 ng/mg) in shrimp embryos. As development of the embryos nears time of hatch, the ecdysteroid levels increase to approximately 150 ng/ mg, indicating that they may be of embryonic origin and involved in embryonic development. An assay was developed for shrimp VIH, which presumably is a protein. Delay of onset of the next reproductive cycle was observed following injection of sinus gland extracts into shrimp that had previously had their eyestalks removed. A photoaffinity analog was synthesized for the putative shrimp reproductive hormone MF-a terpenoid. This analog, farnesyl diazomethyl ketone (FDK) , was used to demonstrate the presence of specific binding proteins for MF in shrimp hemolymph. (PDF file contains 136 pages.)

Additions to a revision of the shark genus Carcharhinus: Synonymy of Aprionodon and Hypoprion, and description of a new species of Carcharhinus (Carcharhinidae)

Features of the valid nominal species of Aprionodon Gill (isodon Valenciennes) and Hypoprion Muller and Henle (hemiodon Valenciennes, macloti Muller and Henle, and signatus Poey), plus those of a previously unrecognized species here described as Carcharhinus leiodon n.sp., are examined and compared with those of Carcharhinus Blainville. Features studied include morphometrics, vertebral numbers and other vertebral characteristics, tooth numbers, color pattern, and some other aspects of external morphology. It is concluded that on these features C. leiodon n.sp. is entirely encompassed within the parameters of Carcharhinus, and that, although A. isodon, H. hemiodon, H. macloti, and H. signatus each extend the range of diversity of Carcharhinus in one or more features, A. isodon is not uniquely different from Carcharhinus, and there is no common pattern of difference between the three species of Hypoprion and Carcharhinus. Accordingly, and because the nature of the teeth of Aprionodon and Hypoprion has been found insufficient to warrant generic distinction from Carcharhinus, the genera Aprionodon and Hypoprion are synonymised with Carcharhinus. A diagnosis and description are given for each of the above species. The descriptions include measurements, counts, and line illustrations that show the whole shark in lateral view, underside of head, nostril, and teeth. The geographic distribution is summarized, as are also the meager biological data available on number of embryos, size at birth, size at sexual maturity, and maximum size. (PDF file contains 32 pages.)

Auswirkungen der Wassertemperatur auf die Missbildungshäufigkeit pelagischer Fischembryonen

Malformation rates in embryos of dab, whiting, cod, flounder and plaice have been monitored for several years (1984-2006) in the Southern North Sea. For embryos of all species investigated trends for the fluctuation of malformation rates over the time were registered in the areas showing intermediate prevalences at the beginning of the studies in 1984 and maxima in 1987. Thereafter for all species a decrease of malformation rates was found until 2006 excepting an increase in 1996. A significant negative correlation existed between surface water temperature and prevalences of malformed embryos of dab and other species.

Der Fischei-Test: Ein Toxizitätstest für ökotoxikologische Untersuchungen

Zebrafish (Danio rerio) embryos have been used to quantify the teratogenic potential of environmental samples and harmful substances respectively. The short spawning interval renders this species a good test organism in toxicological research. Due to the transparency of the eggs several lethal and non-lethal endpoints can be detected in parallel after 48 h of embryonic development. Zebrafishembryos have been shown to be sensitive to a number of environmental relevant contaminants, as well as to ex-tracts from polluted sediments

Zusammenhang zwischen Schadstoffen aus der Elbe und missgebildeten Fischembryonen in der Deutschen Bucht.

The trends of malformation prevalence in embryos of dab, Limanda limanda, in the southern North Sea after the year 1990 mirrored the drop in major pollutants in the rivers draining into the German Bight. Despite this general decline we detected a pollution event in the southern North Sea in winter 1995/1996 employing the prevalence of malformations in dab embryos as an indicator. An abrupt rise in malformation prevalence in the embryos of dab, corresponded to a dramatic increase in DDT levels in parent fish from the same area, indicating a hitherto unnoticed introduction of considerable quantities of DDT into the system. This input could be traced back to discharges of unknown origen into the River Elbe.

Embryonic development in Clarias gariepinus under laboratory conditions

The embryonic development in Clarias gariepinus was studied under laboratory conditions. The developmental stages of eggs starting from first cleavage were examined microscopically. Photomicroscope was used to take important stages of segmentation, blastulation, differentiation of embryo and hatching. The films of the photograph were developed and printed for each stage produced. The accurate timing and detailed description of each stage was done. The results show that the blastodisc (Polar cap) appeared about 35 minutes after fertilization and the first cleavage dividing the blastodisc into two blastomeres occurs 15 minutes after polar cap formation. Details of the developmental stages of embryos and the timing from one stage to the other were described. The larva shook off the shell and emerged completely from the egg case about 22 hours after fertilization at a water temperature of 25.1 degree C. The accurate determination of the time of initiation of first mitosis is of great importance in fish culture and breeding especially in the production of tetraploids

Wassertemperaturen und Häufigkeiten von Mißbildungen pelagischer Fischembryonen

Malformation rates in fish embryos have been monitored for several years in the Southern North Sea. Their occurrence was interpreted to be related to pollution because malformation rates were highest in near coastal waters known to receive high pollution loads. For embryos of all species investigated synchronous trends for the fluctuation of malformation rates over the time were registered in the areas covered with intermediate prevalences at the beginning of the studies in 1984 and maxima in 1987. Thereafter malformation rates of all species decreased significantly followed by an increase in 1996. It was found that a significant negative correlation between surface water temperature and prevalences of malformed embryos of dab (Limanda limanda) and other species existed over time and space. These correlations became increasingly visible with decreasing concentrations of organochlorines in livers of dab. From these findings it is concluded that temperatures possibly predispose developing fish embryos to the impact of pollutants.