Combined effects of ethanol and cinnamaldehyde in the Japanese medaka embryo-larval assay (MELA)

The Japanese medaka (Oryzias latipes) was used in the medaka embryo-larval assay (MELA) to determine possible adverse developmental effects of ethanol and the spice component, cinnamaldehyde (CAD). Fish may be exposed to waterborne ethanol and a variety of natural products from non-point sources or leaks during ethanol use as a fuel and from point source processing plant effluents. Consumption of ethanol during human pregnancy is known to cause fetal alcohol syndrome (FAS), a collection of birth defects including craniofacial abnormalities thought to be caused by the generation of free radicals during ethanol metabolism by both alcohol and aldehyde dehydrogenase(s). Fish are also susceptible to FAS (Dasmahapatra et al., meeting abstract). The activity of aldehyde dehydrogenase is inhibited by CAD [Biochem. J. 282 (1992) 353-360; Biochem. Pharmacol. 45 (1993) 1621-1630], and CAD is known to cause developmental abnormalities in the rat [Food Chem. Toxicol. 27 (1989) 781-786]. Therefore, the combined effects of treatment with both ethanol and CAD would be expected to produce additive or greater than additive effects in the MELA assay. Medaka were exposed to ethanol at 100 mM, CAD at 10, 1.0, 0.67 or 0.50 mM, to ethanol and CAD combined, or were non-treated controls. Ethanol at 100 mM was without effect. CAD alone at 10 mM and 1.0 mM was lethal by 1 dpf. Embryos exposed to 100 mM ethanol and 0.67 mM CAD exhibited cardiovascular and pigmentation defects and delayed hatching. Embryos exposed to 0.50 mM CAD alone had less severe cardiovascular problems as compared to the combined ethanol and CAD treatment. Taken together the results indicate that the combined effects of ethanol and CAD are greater than the individual effects and indicate the need to monitor effluents in fish nursery areas to protect natural fish populations. Supported by PHS/NIH ES07929.     

Evaluation of the leukoproliferative response of English sole (Pleuronectes vetulus) as a biomarker for immune dysfunction

The leukoproliferative (LP) response of splenic leukocytes from the marine benthic fish, English sole (Pleuronectes vetulus), stimulated with the mitogens lipopolysaccharide (LPS), concanavalin A (Con A), and pokeweed mitogen (PWM) was examined as a biomarker of immunotoxic effects. English sole were exposed to an organic-solvent extract of a sediment contaminated with polycyclic aromatic compounds (PACs) or placed on a reference sediment modified with the PAC contaminated sediment. For both treatments, English sole had an augmented LP response to Con A, no significant change in the response to LPS, and the LP response to PWM showed no consistent relationship to exposure to PACs. In a field study, English sole from a contaminated site had a significantly augmented LP response to Con A and PWM. Fish from a non-urban site also had an augmented LP response to Con A and to LPS relative to fish from another non-urban reference site. Overall, the results demonstrated that although the LP response in splenic leukocytes of English sole to Con A was linked to contaminant exposure, the LP response to Con A did not exhibit high specificity as an indicator of chemical contaminant exposure. However, the concerted use of Con A, LPS, and PWM allowed for identification of apparent chemical-contaminant induced alterations of the LP response in English sole from an urban area of Puget Sound.     

Seasonal dynamics of Zostera noltii hornem. In the bay of arcachon (France)

Seasonal dynamics of Zostera noltii was studied during 1984 in Arcachon Bay, France. In this Bay, Z. noltii colonizes 70 km², i.e. approximately 50% of the total area, while Z. marina occupies only 4 km². Densities and length of vegetative and generative shoots and above-ground and below-ground biomasses were monitored in four meadows which differed according to their location in the Bay, tidal level and sediment composition. Three of these meadows were homogeneous, well-established beds whilst the fourth was under colonization and patchy. Shoot densities and maximal below-ground biomass were lower in the inner silty seagrass bed than in the sandy meadows located in the centre of the Bay. Maximal above-ground biomasses were similar in the two population types. In the well-established beds, vegetative shoot densities, above-ground and below-ground biomasses showed a unimodal pattern with minima in winter (4000 to 9000 shoots·m⁻², 40 to 80 g DW·m⁻², and 40 to 60 g DW·m⁻², respectively) and maxima in summer (11000 to 22000 shoots·m⁻², 110 to 150 g DW·m⁻², and 140 to 200 g DW·m⁻², respectively). Reproductive shoots were observed from the beginning of June until the end of September, except in the colonizing bed where they persisted until December. Furthermore, in the latter, maximal reproductive shoot density was higher (2600 shoots·m⁻²) than in the established beds (650 to 960 shoots·m⁻²). The total production of Z. noltii in Arcachon Bay was estimated to approximately 35.6·10⁶ kg DW·y⁻¹ (19.4·10⁶ kg DW·y⁻¹ for above-ground parts and 16.2·10⁶ kg DW·y⁻¹ for below-ground parts).     

CO2 release due to impact devolatilization of carbonate: Results of shock experiments

A study of pure, single crystal calcite shocked to pressures from 9.0 to 60.8 GPa was conducted to address contradictory data for carbonate shock behavior. The recovered materials were analyzed optically and by transmission electron microscopy (TEM), as well as by thermogravimetry (TGA), X‐ray diffraction (XRD), and Raman‐spectroscopy. In thin section, progressive comminution of calcite is observed although grains remain birefringent to at least 60.8 GPa. TGA analysis reveals a positive correlation between percent of mass loss due to shock and increasing shock pressure (R = 0.77) and suggests that shock loading leads to the modest removal of structural volatiles in this pressure range. XRD patterns of shocked Iceland spar samples produce peaks that are qualitatively and quantitatively less intense, more diffuse, and shift to lower ^o2θ. However, the regularity observed in these shocked powder patterns suggests that structures with very uniform unit cell separations persist to shock pressures as high as 60.8 GPa. Raman spectral analyses indicate no band asymmetry and no systematic peak shifting or broadening. TEM micrographs display progressively diminishing crystallite domain sizes. Selected area electron diffraction (SAED) patterns reveal no signatures of amorphous material. These data show that essentially intact calcite is recovered at shock pressures up to 60.8 GPa with only slight mass loss (~7%). This work suggests that the amount of CO₂ gas derived from shock devolatilization of carbonate by large meteorite impacts into carbonate targets has been (substantially) overestimated.     

Semi-structured interviews on disaster and emergency preparedness for people with disabilities in two states in Mexico

Natural Hazards - When a disaster occurs, people with disabilities are at a higher risk to adverse health outcomes due to inadequate access to resources, high levels of exposure to hazards, and an...     

Biodegradation of riverine dissolved organic carbon in five estuaries of the southeastern United States

The biological turnover of riverine dissolved organic carbon (DOC) discharged into five southeastern United States estuaries was examined in long-term respiration bioassays. Measures of bacterial oxygen consumption indicated surprisingly large differences in the inherent biodegradability of DOC among the five estuaries, despite their close geographic proximity. Differences of up to 13-fold in biodegradation rates were also found temporally within a single estuary. For most of the southeastern United States estuaries, measured rates of riverine DOC biodegradation were low relative to rates reported for other freshwater and marine environments. This was particularly true for the coastal plain (“blackwater”) rivers that contribute about 35% of the riverine DOC exported to coastal marine environments in this region; extrapolation of biodegradation rates to the adjacent continental shelf predict biodegradation of a maximum of 11% of exported blackwater DOC within the estuary-shelf system (with transit times of up to 140 d). DOC from Piedmont rivers was more biologically labile, with maximum losses of 30% predicted within the estuary and adjacent shelf. Short exposures to natural sunlight increased the lability of the riverine DOC and enhanced biodegradation rates by over 3-fold in some cases, although significant inter-estuary differences in susceptibility of riverine DOC to photolysis were also evident. *** DIRECT SUPPORT *** A01BY085 00007